Brian Armstrong has released Bitcoin for Android as a free and open source application to the Android Marketplace (https://market.android.com/details?id=com.bitcoinandroid).
It's a very slick way of sending and receiving Bitcoins on your Android phone. Easy install, but make sure that you do it over Wifi since it provides a recent block chain to get you up and running quickly, and that's a few megs.
Technically minded folks who want to examine the source code to verify that it's not going to rip them off can do so at GitHub (https://github.com/barmstrong/bitcoin-android).
Receiving coins can be done by instant QR code generation (so another phone can view the screen and pick up the wallet address), or by sending the wallet address via almost any mechanism you can think of (SMS, email, Twitter, Facebook, FriendStream etc etc). It will copy the wallet address to the clipboard if you want to allow you to paste it anywhere you like.
Sending coins can be done by either scanning a QR code (ideal for merchants presenting prices in BTC) or by manual entry (from clipboard if necessary).
It's really aimed at keeping pocket change available for small day to day transactions since your phone could be stolen (just like a real wallet could be picked) and for that it's an excellent choice.
Give it a go and continue to build the Bitcoin economy - the merchants need you :-)
