I hope to see you out there this August...we are shooting for a start date of 8-1-07. I have thru-fished the JMT 3 times (02,03,05) and can say it is fantastic! My journals fish counts are 72, 78, and 87 respectively (all released).
Like the other posts, I have been bored of catching soooo many trout (23 in under an hour at Rae Lakes and Donahue high mountain lake)...they seem to be 6" to 8" range most of the time but I have landed some 12/13" at Purple Lake, Garnet Lake, and Cathedral Lake..the larger trout have all been rainbows while the small but fiesty brookies and golden trout are the usual catch.
I saw a guy flyfishing Cathedral lake using a wet fly (black wooley) and he landed a 15" rainbow- absolutely amazing fish!
Gear: I use a two-piece spinning rod (this year I dropped the money for a beautiful 5' two piece G-Loomis as I KNOW how fun the Sierra can be with a good outfit)reel is a micro light by Shimano, 2 lb test is plenty, 3 lures in a film canister.
Lures are 1 rooster tail, 1 mepps spinner, 1 panther martin
that's it..all you need.
Hollywood should film,"Field of Streams"...if you cast it, they will come!
The Sierra and JMT is awesome for small trout action. Try the streams that parallel the trail- just look for a quiet pool or some clear water, throw it in, and let the fish fest begin!