Picked up my bass again after many years of not playing, (uni, work, video games, new house, etc), and I cannot play at all! My left hand is moving just out of sync with my right hand so it makes that horrible twangy sound all the time, can't remember any songs, and the riffs I do know sound bad and sloppy >.<
Do I need to go right back to basics? Or are there any good tutorials or tips out there on getting back into playing properly?
Any skill, including playing a musical instrument, will atrophy if not used. But as the old saying goes, "It's like falling off of a bicycle, once you know how, you'll never forget." I would recommend doing the same things anyone has to do in order to regain any lost skill. Go back to the fundamental basics, and then don't be surprised if the dormant muscle memories revive and you're back up to speed fairly quickly. Any tutorial or lessons out there for beginners are going to be reasonably good for making a comeback. Just don't be surprised if you find it all coming back to you a lot quicker than you thought it would. 
gerdner Nice, cheers for that. There's a lot of resources and videos out there, do you guys here have material or could recommend some?