1) Reload my RSS feed from FishEye - if it's returning invalid XML, I know something's up.
2)Check the files.wowace.com page - if it's down, I just wait 'til everything's back up.
I generally check the RSS feed before I update anyhow, as I can see if there's any updates I need/want before I open WAU. I recommend reading the commit logs on the AddOns you use. I've often been able to just implement the change myself and save a little server load. If it means adding or subtracting a bit o' code, I can do that. The diff in the FishEye page for the commit tells you what lines and highlights the changed areas, both on the line numbers and in the text itself. A good text editor is all you really need - and a quick search I know will find a couple-three threads on that topic.