In reply to thomb:
I've actually just moved back from BC - You've picked an awesome place to visit!
First thing, Squamish is an incredible climbing destination. I'd rank it up there with Yosemite/ the Creek/Smith rock. it's totally a must visit.
For alpine climbing in BC the go-to resource is alpine select. If you visit squamish camp ground i'm certain there's plenty of people who could show you a copy. (those i know will be in the bugaboos/rockies through august i'm afraid)
http://www.mec.ca/product/4016-745/alpine-select-guide/
There's the tantalus range, which is close to vancouver. Its a dramatic area, not huge technical difficulties (unless you want them) but big on adventure (lose rock etc).
For maximum rad points i'd recommend doing the 'Tantalus traverse'. google should give you trip reports. Huge amounts of interesting terrain in a really spectacular location. It's pretty physically brutal though. It can be done by helicopter (generally recommended). I did it on foot - more peaks, more value! (this turned it into four - huge - day mission including river crossings, bush whacking and a tyrolean traverse. recommended for an epic)
You're biggest problem will be glaciers. BC had a fairly low snow year, and i think by august they're going to be really broken up. I was in tantalus at the start of this month and things were still in good nick. Ask the locals!
... yet another reason to go to squamish.
You're other option, which is probably the best one, is the Bugaboos. A collection of amazing granite spires all centered around one hut/camp site. It's a really world class alpine destination and August is the prime time of year to go there. It has its own guidebook.
Enjoy!
let us know how it goes
Edit: the bugaboos aren't that far from nelson
Post edited at 11:03