One of all the best parts of having an iPhone means you should have everything accessible at all times. I was looking at all the wine apps back in December and decided on Drync. They just came out with an update and it resolved a lot of the issues that I had with it.
The number one issue that I have with it is that all the data is stored online, that means that if you have an iPod Touch you have to have WiFi to see your cellar.
Number two is that if the software can't find the wine online you can't add it. There is now a way around that if you find something similar you can add it to your cellar and then change the name and info. So if there was a 2000 but you had a 2001 you can add the 2000 and then just change the year.
The biggest thing that the update fixed for me is being able to edit the information for a wine. If the search came up with no price you couldn't add it. Same with stuff like varietal and region.
Some nice features are that it will find reviews and you can also buy it online.
I picked it up for a dollar, but it's now up to $4. Still worth it though.