Does Avast work well in conjuction with Online Armour?
Yes, afaik.
Online Armor Free, yes.
Online Armor ++, no because it has an antivirus also.
If i used it i would need to turn off the firewall in avast, right?
Yep. 
Don’t know about that, but I do know that Avast works well with Onbody UnderArmour. 
OA++ actually works fine with all versions of Avast! Even the AV is designed for non-interference (scan on execution). But something you don’t really need with Avast!; I only have ++ because I am a beta tester for OA. But I do exclude Avast! from monitoring by OA, and some also exclude OA from Avast! although I haven’t needed to. If you have AIS, you actually need to go to Programs and Features and uninstall the Avast! firewall before you install OA.
Yes. Turn it off permanently if you’re using AIS before moving to OA.
But, why are you moving from AIS to OA?
I am not actually moving from AIS to OA it’s just that i have seen a few people on here use it and wondered why they chose to use that instead of just using the AIS firewall :-\
Ok justinlee
I use OA primarily because it contains a good HIPS-Avast! has no HIPS at all. My use and familiarity with OA also predates the AIS firewall. I don’t mind answering popups and taking a bit more manual control of the system. If you don’t want to be bothered as much, Avast! has a perfectly adequate firewall, including packet filtering rules, and substitutes the evolving Behavior Shield and the Sandbox to try to accomplish similar results without as much intervention on your part. I beta test AIS alternatively with OA and recommend both depending on user preferences.
What is HIPS?
A HIPS is a Host Intrusion Prevention System that watches over your processes and informs you with a popup when one does something that might indicate malware. See http://forum.avast.com/index.php?topic=78200.msg647021#msg647021 for a very brief discussion of HIPS, firewalls, behavior blockers, the end of the world, … :o But if you are not already comfortable with HIPS type functions, the behavior blocker/sandbox gives good protection without it. If you want to learn a lot about popular computer security and the endless YouTube tests, HIPS is the main underlying subject there.
What is Google ;D
Host Intrusion Protection System.
HIPS is a fw doing an antivirus’ job and an antispyware/antimalwares job.
On my systems ZA does it’s own job and MSE does it’s own job.
IMHO, things work better that way. 
Seems you don’t really know what HIPS is and the capabilities it has…
I gave a simple explanation, I wasn’t being technical. Most HIPS are in fw’s.
WinPatrol’s HIPS are enough for me.
Personally I would exclude avast folders in OA options>exclusions and vice versa in avast exclusions (file system shield ,behavior shield and exclusions in basic settings, and would also disable (from OA tray icon) its web filter (avast already has a good web filter.Ive personally found the OA web filter can cause slowdowns and hangs when visiting pages ,where you may have to refresh the page a few times.No such problems when its disabled.
miscreant