The "IC Piano Tuner" Turn your computer into a tuner -- View Pitch & Beat Real Time!
It comes with affordable price. It revolutionizes the approach in traditional tuning software by focusing on beating, the key task for tuners.
(1) It covers all keys from A0 to C8 for a standard piano keyboard. (Most other tuners & software have difficulties in identifying lowest keys such as A0).
(2) Beat counting is a major task in tuning. Did you ever have problem with it? IC Piano Tuner transforms the beat into visual result, no need for a metronome.
(3) In "Pitch" Running Mode, it can also provide partial-by-partial beatings between two strings (e.g., 4:3 & 8:6 beatings for F3 & A#4).
(4) In a noisy background while working with your piano? IC Piano Tuner allows you to set the cutoff level for the noise.
The latest version includes even more powerful features such as,
(i) In Pitch mode, user can play two strings at once for a quick checkup of partial beatings for, e.g., perfect fifth.
(ii) In Beat Viewing mode, higher partial beatings (such as 3:2 of perfect fifth) which are usually obscured by the first (or lower) partials can be enhanced by a simple click.
(iii) User is provided with an option to reduce the impact of the piano hammer knocking noise to achieve better tuning accuracy.
(iv) User can choose different keys for higher pitch or higher partials beating enhancement.
(v) Reference marks of equal temperament beatings are provided real time on the beating graph in Pitch mode to assist tuning practice so one does not have to memorize the equal temperament beating values, e.g., 0.89 Hz (Narrow) 3:2 of perfect fifth beating between C4 and G4.
It is expected this forum will be able to allow the user to post questions and exchange experience so we can improve the software to serve the tuning community.
Bill
https://www.cc-ast.com/icpianotuner.html
Reply on April 11, 2015 for comments below:I am glad to hear comments coming back, as most users are too busy in tuning

. I hope authors from other tuning software can post their comments too regarding their software, since they are those most familiar with their products. Then we will be able to have fair view while comparing pros and cons of each other.
Regarding to comments of "sk8nfool",
I don't know what you expect from "real time". For IC Piano Tuner, it needs time to listen to the sound as all other software as well as a technician. As long as it finishes listening (recording), the results should come out almost immediately, since the analysis is a simple process compared to other computer engineering tasks and does not consume a lot of computer calculating power. If there is a significant delay, it is more likely your computer has other time consuming tasks running on the background. In this regard, The pitch results are regarded as "real time", since you see the result right after you play a string, not after you click something else (to save, to analyze,...). I expect most other tuning software follow the same way. The major difference IC Piano Tuner brings in compared to most of the others is, it provides time (when button color at green) to allow a user to reads and digests the results, and notify (the button at yellow) the user when it is ready to take next play. I have tried some other software which appears to have continuous sampling function (which typically use a shorter time and has poorer resolution) and noticed I have to keep knocking the key several times, since sometimes it does not pick up the play and it seems to have some delay so I am not sure when the sound is picked up. I have been considering to allow user to define their time for listening (red button), reading (green button), waiting (yellow) in the future release (which is a little bit against my original goal to make it as simple as possible).
For "real time" beating, it is more straight forward in Beat viewing mode, since the display shows you the visual beating with the sound curve going up-and-down while you are listening to the beat (It seems to me "sk8nfool" is expecting number(s) for the beatings which are available in Pitch mode for two string beatings). The beating value can be seen easily within each one-second division (how many times the curve goes up-and-down). The sampling is continuous, so it can even show your voice beating when you are talking. A special feature here is it can enhance higher partial beating (e.g., 3:2 beating) so to reduce the impact from the 1st partials which are usually the loudest. So far I have not seen any other tuning software providing beating functions as above. For the "Audacity" software mentioned by "pristinepiano" below, I spent 5 minutes trying to figure out what it is for, I have to say I am not smart enough to connect it with piano tuning so quickly. It is likely "Audacity" is not specifically targeted to piano tuning. According to the description by "pristinepiano", apparently you will need to spend significant amount of time on configuration just to get the simplest beating result. It may be helpful if "pristinepiano" can post further detail about how it works.
You can get more information by clicking the "help" button when you run IC Piano Tuner.
For beginners, I would suggest tuning steps as,
(1) Mute all strings (or as much as possible) except one for all keys;
(2) Tune A4 to the standard;
(3) Tune other keys within one octave (e.g., from C3 to C4) according to perfect fifth and perfect fourth;
(4) Tune other octaves according to tuned keys in (3);
(5) Tune 2nd unison (keep 3rd string muted if presented);
(6) Tune 3rd unison.
You may need to iterate more as needed, since tuning one string may off-tune the others. From time to time compromises are required (i.e., impossible to achieve perfect tuning) due to special conditions.
It seems to me people are trying to push me to increase the price for whatever reasons among which the main argument is cheap means low quality. In general they are correct, but for IC Piano Tuner it does not apply (well maybe one day it could come true if we skyrocket the price). At current stage, we are trying to make it affordable for many of the tuning amateurs.