dblondin has an interesting tutorial on how to make light saber sound effects using vibrators, old TVs and plug-ins:

Accent Hum:
When a lightsaber swings aggressively or when tension is rising, the oscillators should sound more fierce and electrifying. This can be achieved by creating accent hums, which are basically just different versions of the high and low oscillator. To create them, you can either make processed versions of your hums or synthesize new ones from scratch. A quick and effective technique is to simply run your hum through a distortion plugin such as iZotope Trash. Trash will really allow you to change the personality of your lightsaber sounds and is especially good at energizing weak sounds. It is not absolutely necessary to record the accent hum in motion with your microphone. During the edit-to-picture stage, you can just layer some accent hum in here and there using volume envelopes.

Power Up/Down:
For the blade open and close effects, you can be very creative as these vary quite a bit in the films. I found that the sound of a solid fuel rocket launch is a good starting point, as is a credit card sliding across plastic laminate (such as Formica), or even chalk on a blackboard. If you bend the pitch of these sounds upward it sounds like a lightsaber blade opening and the same sounds in reverse work for closing. In fact, any smooth “pssshhh” type sound will work and I have no doubt that, with a bit of processing, you could even use your mouth to create it.

Clashes:
For the blades colliding, look no further than electrical zaps. You can design these effects with microphones, synthesizers and effects processors. However, since this topic is so complex, it will require its own web page. Therefore, unless you already know how to create these sounds, I am going to recommend that you use commercial sound effects from such retailers as sounddogs.com. If you just can not cope with that (which I sincerely hope) it is possible to create these sounds using car batteries. Check out this page on epicsound.com for more information.

Preview the results below, and check out the full article. It has a lot more info and is an eye-opener on sound design.