I don't know how many of you read Baseball America, but the most recent issue (on newsstands now) has a great article on Felix.
With regards to teh question as to when he'll reach the big leagues, Seattle's VP of player development and scouting said "...the ideal circumstance with Felix is that he finishes the year in Double-A and begins next year in Triple-A...How much Triple-A experience does he get? I don't know. He may pitch so well that he forces us to put him on the big league club."
The article also talks about the fact that they have an inning limit in mind for Felix but aren't telling him what it is, though I would guess that he only starts one or two more games. Another interesting tidbit is that he is under control to Venezuela's Lara Cardinals, so he may pitch again this winter, though probably not much.
There basically hasn't been a pitching prospect like Felix Hernandez since Dwight Gooden in 1983. It's hard not to be excited about the kid even if you aren't a Mariners fan. I just hope for his sake and the Mariners and baseballs that he stays healthy. His potential is unlimited.