I am using Avast4 Build: 4.6.739
and Vista Build: 5321
The problem is everytime I start windows my internet connection works (MSN Messenger, etc.), but I can’t get to any page with my web browser! (I tried IE and Firefox)
I have figured out that when I right-click my Avast! icon and do “Stop On-Access Protection” and then turn it back on → Web browsers are working! 
You have to always keep in mind that Windows Vista beta is OS which is still under development. It’s gonna be long enough until it goes Gold, so I’m sure Alwil guys have plenty of time to play with those issues. Right now, priorities are current OS issues.
Btw, I have Vista Pre-Beta2 on my test machine and everything seems to be working fine. No problems with internet connection whatsoever.
Regards
Well, is there any way to start Avast! services after the net services?
As far I know, Windows Services delays are not configurable.
They will start, like startup programs, in an order that can’t be changed by the user without a 3rd party application.
For programs there is such application, for services I never found.