Here's my post from another thread:
Belkin offers an adapter for the iphone, which is available at the apple store too. Unfortunately, the Belkin adapter is long and sticks out of the jack like a huge grey antenna. However, I discovered another solution to the problem from another forum. If you buy an Apple iPod shuffle sport case, it comes with an adapter that deals with this issue. It's more of an extension cord design that was made because the case design prevented headphones from seating all the way into the headphone jack on the shuffle. Here's a link with a pic and further explanation:
http://www.penmachine.com/2007/07/this-adapter-from-sport-case-for
The case that includes the adapter costs $29 at the apple store. However, I was able to get one on eBay for $4, including shipping. There seemed to be quite a few available too. Finally, Griffin has created an adapter that looks like the same design, but it isn't available for purchase yet. Unlike the sport case adapter, which comes only in white, Griffin's will be available in black or white.