If you haven't done so already, you need to start updating your Addons now. Patch 3.0 will break most if not all of your mods. Most of the popular Addon sites will be flooded right after Patch day.
I started last night gathering mods. I found most sites (with the notable exception of Curse) made it very easy to tell if a Mod would work with 3.0/Wrath. I also have the added bonus of being a Beta tester, so I can test the mods on the Beta client.
So far, I've downloaded most of the mods I need. I've only installed Xperl on the Beta client but it seems to be working just fine so far.
I'm taking it slow because I really want to redo my UI for Wrath. I'm took much of a clicker right now. I don't click everything, but I still click too much. I want to build some new habits as I level in Wrath.
So far I've downloaded : Auctioneer, DeadlyBossMods, Decursive, ElkanoBuffBars , FuBar , Healbot, ItemRack, OmniCC, PallyPower, Prat, RatingsBuster, SCT, SCTd, Tankadin, tekKompare, Xperl
I haven't found a Wrath version for: CEnemyCastBar, Durability_Fu, Grid, MobInfo, Performance_Fu, OneBag, OneBank
I don't need some mods anymore: Omen, Clock_Fu
Edit 10/14: I just found a great site to help me out, and I'll share it with you: http://www.wowinterface.com/survivalguide.php