Hey David,
For starters, list them in posts in the appropriate thread areas on sites like GayDemon, GaywideWebmasters.com, gofuckyourself.com sell and buy, Xbiz.net’s Opportunities/DomainNames, and so on. As to companies that are professionally selling a domain on your behalf, I can’t honestly recommend anyone in particular, as I haven’t used them personally. Perhaps other members here can point you in the right direction.
No it’s ok, you can create another post with them for sale in the other category too. But you might also want to put them up for sale on somewhere like sedo.com
As Bjorn mentioned, this area was perfectly fine as you were asking for help and information, it wasn’t a post listing your domains and putting up prices.