Rumor has it that one of the next incarnations of the iPod will include wireless connectivity. Whether that means bluetooth, 802.11, IR or some other technology remains to be seen.
So, for now, you're probably stuck using a bulky adaptor. I found a lot of hits googling for "bluetooth headphones" and "wireless headphones" -- too many to list here, plus I don't know exactly what you're looking for.
Maybe someone with some experience with wireless headphones will chime in -- plus, there's always ipodlounge.com that has great reviews for all sorts of iPod accessories.
*smiles* I got home and found a foot of snow waiting ( I live ~35 miles from work in a pretty rural area ) and immediately fired up the leafsnow blower and got to work It's my first time using it since I got it a few weeks ago. 10 minutes and my driveway and sidewalks were clear. We're expecting a bit more leaves snow tonight, so I get to play work on it some more tomorrow
Wearing the iPod, of course.
*radio edit* Other forums use ... to do strikeout, so forgive the messiness above. (sigh)