Ebikekit is offering a $100 rebate off any installed conversion kit purchased on Earth Day next Friday, April 22. They're carried (& installed) locally at The eBike Store, 201 N Alberta. Retail price depends on exact configuration, but my back-of-envelope calculation is about 10% off.
Conversion kits are a great way to breathe a bit of fresh air into an old friend. If you've got an old bike lying around, it may be a great candidate for a conversion. Also, the Community Cycling Center and City Bikes have very reasonably priced used bikes. There are some particulars about converting a bike (mostly details about the front forks), so you may want to call and ask about the details before you buy a bike specifically to convert.
Details can be found here: