Squarespace have a fun little service for non-design people needing a logo in a hurry. Using a very simple interface, users can select a symbol from a fairly extensive library, add their business names in one of a few quite decent open source typefaces, tweak the colours and positioning and add a tagline. The design can be previewed for the web, t-shirts and as a business card, and also saved as a png file. For design that actually works, please see your graphic designer.
Remember those endearingly plain pictograms that first gained popularity in the 1970s? Designed to transcend text and communicate simple concepts/commands, pictographs are still a staple of the sign world. Victor Hertz has employed the pictographic vocabulary to amusing effect, creating pictographic posters for a raft of movie classics. Beside the whimsy, it is a very interesting design exercise to be forced to boil a complex idea down to simple iconic image.