Free update (says me hoping?)
Well, to tell the truth, all the current versions of our products have already been tested and work just fine in CS4 (you _DO_ need the most current versions however that are available on the PG web site). The only question is the 64 bit binaries for CS4 64 bit on Win. Those will require work to compile and a new installer to correctly install either the 32 bit or 64 bit versions (depending on the OS). But we're inclined to offer those as a free update, yes.
We are however, working on NEW versions of PhotoKit Sharpener 2 and PhotoKit 2 which will be paid upgrades...they prolly won't launch until early next year.