In terms of PvE, especially raiding, www.elitistjerks.com is what you want. (--> Class Mechanics forum)
www.wowwiki.com is a good resource to get a basic idea of the game and the classes themselves. There are PvE-, PvP- and Starter-Guides for every class, tactics, talent builds and everything you want. (although sometimes a bit outdated, so if you want exact information for lvl70 raiding you need to consider reading somewhere else)
www.shadowpanther.net is a cool site for Rogues as it lists all items for lvl70-Rogues in a pretty good order, you should consider a spreadsheet for raiding though since spreadsheets suggest new items based on what you already have and depending on the talent specialization you prefer.
There are lots of guides for every talent spec of every class I could link to, but I think these are the most important sites that you need to know. Look around a bit at Elitist Jerks' "Class Mechanics" forum or the "Theorycrafting Think Tank", you will usually find good guides and spreadsheets for every spec there.
www.wowwiki.com is a good resource to get a basic idea of the game and the classes themselves. There are PvE-, PvP- and Starter-Guides for every class, tactics, talent builds and everything you want. (although sometimes a bit outdated, so if you want exact information for lvl70 raiding you need to consider reading somewhere else)
www.shadowpanther.net is a cool site for Rogues as it lists all items for lvl70-Rogues in a pretty good order, you should consider a spreadsheet for raiding though since spreadsheets suggest new items based on what you already have and depending on the talent specialization you prefer.
There are lots of guides for every talent spec of every class I could link to, but I think these are the most important sites that you need to know. Look around a bit at Elitist Jerks' "Class Mechanics" forum or the "Theorycrafting Think Tank", you will usually find good guides and spreadsheets for every spec there.