You'll need a blower, brush (like a lens pen), and cleaning cloth + cleaning fluid. (A lens cleaning cloth is reusable and you can clean them, so they're probably more desirable than disposable lens cleaning wipes.) They should be used in that order, to minimize physical contact with the lens (you probably won't need to use fluid + the cloth very often - only for fingerprints, etc.). Really, any kit will do. More expensive blowers are meant to be used on the camera body, so if you've got more than one lens it might be sensible to just get something like a rocket blower.
Lens cleaning cloths are easy to come by, just go in and ask when you're passing by an optician, they'll probably just give you a cloth for free. (This worked for me the last couple of times I needed a cloth while I was out.) Oh, and if you do use the cloth + fluid, remember to apply the fluid to the cloth, not the lens surface - the fluid evaporates really quickly, but it's still pretty unpleasant to see fluid leak in behind the front element!
If you've got more than one lens you might want to clean the sensor yourself at some point, in which case it's blower then fluid + wipes/wand, again in that order (if necessary). I'm using swabs and fluid from VisibleDust, but Eclipse is really popular too.