Matt has already covered a number of options, which I won't try to repeat here.
Unless I missed something, he did miss one possibility though: this is to use a relatively long lens on the camera, with a relatively short lens, reversed, in front of it. This is basically the same as the closeup-lens option Matt did mention, but instead of buying a new closeup lens to use, you use a lens you already have with a dirt-cheap reversing ring (basically, just a hollow tube with filter-sized threads on both ends).
Getting this to work well can be somewhat challenging, to put it mildly. In particular, it's often worthwhile to do a bit of experimenting with free lensing to find a combination of long and short lenses that happen to work well together, and only when you've found a good combination, buy a combination of reversing ring and (if necessary) step-up or step-down rings for that pair of lenses. Of course, it's also nice if you have two or three different lenses with the same size filter ring to use as the front element.
While this option does take more work than buying closeup lenses, it generally gives better results. A closeup lens is basically just a short focal length lens -- but the cheap ones are uncorrected single-element lenses, while the more expensive sets are two-element lenses to give marginally superior correction. Even those, however, generally have pretty poor correction compared to even a cheap 28, 35 or 50mm lens.
One other point: since you're using the front lens reversed and ignoring its normal lens mount, you do not need something that would otherwise fit your camera at all. A lot of older, manual-focus lenses work nicely, and can be picked up for next to nothing.