Here is a good forum/site...the link takes you to the hunter class forum, they have a pretty detailed FAQ for hunters at the top that helped me a lot when I first started.
http://wow.allakhazam.com/db/class.html?wclass=5
As for addons, I use a bunch of different stuff, but simply starting out, google Cosmos, get the complete packagage and Auctioneer...they will make life much easier. There is also an addon called Auto X...which when you go to vendors it will auto sell all greyed out items.
-Use auction house always to sell stuff off when possible, you will always make much more than at a vendor.
-If its your first character...get gathering professions such as mining and skinning...easy to level and you can offload ore and leathers quickly and for monies...so you will quickly get gold.
I used two really good guides for leveling when I first started, as WoW took me a while to get a hold of wtf I was doing...they put you on the path of where to go and the quickest routes to getting your character to level 70...if you are not intrested in throwing money at them, you can probably find them through torrents or creative google searches...the power level guide for alliance is Brian Kopps alliance guide and, for horde its Joana's Horde leveling guide.