I recently bought the CanoScan 9000F Mark II Film Scanner to digitize some of the negatives I had sitting around. The 9000F is probably the cheapest way that you can get into scanning your negatives. It does both 35mm negatives and slides, and even does 120 film.
The CanoScan 9000f Mk II does just fin for web uploads, but I would not recommend it for serious printing. Though it advertises a 9600 dpi resolution for scans, the results do not look like the reflect that high or a resolution.
CanoScan 9000F Mark II Results
These are all results from scanning 35mm film negatives. I've added the usual color correction and sharpening using Lightroom. I'm happy with the results, and I hear that scanning 120 film yield even better results.