This is a guide to leveling as rogue. This guide encompasses subjects like leveling, specs and gear.

The class
The rogue is the master of the quick melee kill. Unlike the warrior, the rogue starts at full effiency (100% energy) and relies on burst DPS to survive. With only leather armour, you need to take down your target fast and be careful of adds.

The class is great as a farmer and one of the best damage dealers in the game in groups. In groups the DPS aspect of the rogue really shines through, as some of the higher damge moves are position dependent (backstab) and with a tank, you can really let rip.

Leveling Methods
Rogues are pretty straight forward to lvl and are the perfect grinders. Stealth, sap and distract make rogues able to sneak to most places and complete quests. Sicne rogues are very good at grinding, you can mix quests and grinding more freely, as opposed to the DPS-challenged classes.

The following is a link to the rogue FAW on the US boards, with loads of useful links.
http://forums.worldofwarcraft.com/thread.html?topicId=11381359&sid=1

Whichever you choose, I highly suggest doing nothing but instances from 58-60 to gear up and get all your key quests done. Not doing so, means missing out on a huge amount of XP.

The traditional ways are:

Grinding:
Not much to say about this. You kill mobs, they give XP, you lvl. If you don't have a comprehensive knowledge of where quests take you and which order is best, grinding is pretty fast for leveling.
It can be pretty boring, but listening to music or being on Vent/TS helps a lot. Get a rhytm going and stay in it. Take breaks when you mana up to not go completely blind

The following is pretty good list of where to grind which mobs. It is however from a horde perspective and you need to scroll down a bit to get to the guide If you read the whole bit, there are some suggestions for alternatives, which work just as well…if not better.
http://www.mpsgames.com/ms/index.cfm?page=topic&topicID=31653&categoryid=20&forumid=63

And the following lists some nice alliance spots for grinding. Also are some suggestions on questing.
http://www.wow-pro.com/Knowledge_Base/op=show/kid=515.html

Questing:
If you know your way around the world, this is the fastest way to level up. This is also known as gresting to some. Decent horde guides are few and far between (there are some on this site), alliance have it a lot better.

horde - if you are horde, use Joana's guide. That will take you from 1-60 in 5 days /played. It's written from a hunter perspective, so my suggestion is staggering your progress in the guide by a lvl or two. Other than that, there are some (admittedly with holes in them) guides here in the strat section. An idea is to try and modify the following alliance guide.
http://forums.blizzhackers.com/viewtopic.php?t=309717 is the text guide (thanks Bay_Cassius
http://video.google.com/videosearch?q=wow+world+of+warcraft+levels are links to all the videos (thanks sQren)

alliance - if you are alliance, you got it made! The following guide will quickly and easily take you from 30-60. Reason it's 30, is because of the quests pre that are in and around the starter areas, so just level quickly to 30 and you are set.
http://www.wow-pro.com/node/599

Talent Specs
For leveling I recommend spec'ing for swords. Sword damage rely less on positioning and more on frontal, white/normal damage. If you do 58-60 exclusively in instances, consider spec'ing daggers, since it's a big damage upgrade, but it relies on postioning and a good tank. Considering you may need to PUG instances (and tanks may suck), swords are still very much an option.

This is the spec I suggest for leveling:
http://www.wowhead.com/?talent=f0ecoxxZMhEz0Vzxb

Fill out malice and imp SnD first, then move to combat and fill that out up until swords and blade flurry, then fill out rest of Assasination.

Method of pulling: With swords, you don't really need to be stealthed or positioned, so just pull with ranged and wail on the target. If you are up against multiple hard mobs (high yellow), it pays to sap one and take the others down, then the sapped one. There isn't really any large downtime after a fight, only the need to bandage up every 5 mobs or so (if that).

OneHitWonder is a very useful add-on for grinding, since you can set it up to apply various attacks at the press of one button.
http://www.curse-gaming.com/en/wow/addons-121-1-onehitwonder.html

Gear
Rogues are stuck with leather their whole life, so can't take a beating for too long. Focus on AGI, and lots of it, mixed up with some STAM and STR. Personally, I go all out on AGI and STR to get targets down faster in PVE, but you need more STAM if you PVP. At around lvl 45, you can get the thrash blade from Maraudon, which should last you until 58-60.

The following is a link to a very useful site with loads of gear tables, incl. FR gear.
http://shadowpanther.net/wow.htm

Apart from that, rogue is a very fun class, that is easy to play, but hard to master. When you start raiding, consult this thread on how to maximize your DPS using daggers:
http://www.mpsgames.com/ms/index.cfm?page=topic&forumid=24&topicID=36669&categoryid=20

Enjoy