One of the biggest complaints I have read everywhere is the inability to really effectively search what apps are available for your phone. I have found 3 sites that do a great job of keeping me up to date and also have RSS feeds that are very helpful.
Androlib – this site is perfect for searching what apps are out there, then you can just scan the barcode and find the apps really fast via your phone. This is how I found a ton of my apps and also it has a list of the best of the day applications which I check everyday to see if there are any new apps
Android and Me – This one gives great reviews of applications and what is going on in the Android world
Phandroid – Is probably the most updated and most informational site as to what is going on with the Android community
