Watching eBay, prices really start to jump around mid-September, with prices peaking a couple weeks after Thanksgiving. After that, stores are looking to dump their inventories and everyone's snow lust is starting to be satisfied. Note I said starting. I've found the best deals in April and March on good skis and the occasional steal during the summer on off-sizes and older skis. Probably the worst time to be a seller, but the best to be a buyer.
I'd say that the time to sell to experienced skiers is shortly after the ski mags come out in August. Certainly, less experienced folks will be buying in the pattern that Alaska Mike notes, but with the level of skis that you're selling, Gator, you may find an early attack (before the shops have their new stock available) may be your best bet.