I don`t know of any site like that, unfortunately.
The main thing is to stay in Defensive stance (the pally version is Righteous Fury). You generate way more threat that way.. Make sure to use Sunder Armor on your target, once you have a few stacks on your main target put a sunder or two on the rest (so that AOE doesn`t pull them off). Thunderclap is lovely for keeping AOE aggro.
Be careful how many mobs you pull as a warrior; your aoe abilities generate less threat then a pallies. For paladin the main tanking spell at your level is Consecrate. Actually, it is the main spell at all levels, there are just more of them at higher levels.
If you do happen to lose a mob to someone else, use Taunt (Righteous Defense for pally) to get it back on to you. You tell who has aggro by watching your party members health bars. If someones health is going down, you need to take a look to see if it is because a mob is hitting them, or if it is because there is AoE damage. There are lots of addons and interface options that assist with this to some degree, but I don`t want to confuse you with a ton of stuff when you are just starting off.
Take a look at the glyphs that improve your main abilities, like the one for Sunder Armor and, when you get it, the glyph for Devastate.
You have to remember that it is the parties job to help you keep aggro. Many groups (especially DPS) don`t get this, particularly at low levels, but it is nearly impossible to keep aggro off of someone who pulls. You get a huge amount of threat by being the one that pulls, and if a dps or healer pulls for you, you need to warn them about doing it.. And if they don`t listen, let them have it. Trust me, it makes your life much easier AND it teaches them not to pull it unless they can take it by themselves.
It gets easier at higher levels, when you have more tricks and abilities to help you keep aggro... Hope something there helped, and have fun!