In the Baseball Prospectus Annual, they use to provide adjusted avg, slugging, and obp (adjusted for home park and leagues). However, last year they didn't. You could check their website, click on statistics, then click on Equivalent Average. Every player's listed with an overall Eqa that adjusts for those factors. Thus, if you compare Jeromy Burnitz and Carlos Pena, you'll see that they have very different raw numbers, but Pena actually has a slightly higher Eqa.
The problem with Eqa though is that it doesn't give you estimates of park-adjusted OBP or slugging (as separate components). It also doesn't show splits (v. RHP and LHP), so a player with a large platoon split will show an Eqa that's less than what he'd have if you only platoon him.