Bought a Sandisk Micro U3 2GB flash drive which comes with U3 launchpad version 188.8.131.52. This works in Windows 7 Beta.
Avast! Antivirus U3 Edition (2 months trial) and McAfee VirusScan USB (30 days trial) work in Windows 7 Beta.
The only issue is that both programs conflict with internet connection using 3G which caused the signal to "disappear". But, internet connection using wireless is fine.