This large state park boasts a little of everything, from short sport clip-ups to mixed multi-pitch routes or even long, infrequently traveled adventure climbs. I have only sampled the area, but am writing it up here to get the ball rolling. The crags are sandstone, some reminiscent of the good stuff at Red Rock, NV, some resembling the softer formations of Zion National Park, and some fit for climbing by only the truest of desert rats.
No matter if you are chasing sun or shade, or wanting crimpers, slopers, pockets, or an occasional crack there are climbs of various flavors facing in any given direction at any given time of day, depending on which crag you are at. The Island In The Sky area sports the Aftershock Wall, Circus Wall, The Doghouse, and other walls with good sport and mixed climbs. The West Canyon area has adventure routes and much adventure potential for those looking for touble and in possession of an emergency bolt kit. The nearby town of Saint George has plenty of services and hotels as well as nearby 'improved camping' at Snow Canyon State Park ($14 in addition to $5 daily entry fee) or free camping just outside town on BLM land.
The directions for each individal crag will be more telling, but to reach the state Park entrance, exit I-15 on the Bluff Street (I-15 Exit 6) in Saint George. Go north a few miles to the Snow Canyon Parkway, then left on that for 6 miles to Highway 8, then right (north) on that for ~3 miles into the park. Maps are available for the park at the entry kiosk where they will collect your $5 entry fee.
I kid you not, these directions are listed under the 'season' section of the Goss guidebook.
Two summers ago a couple friends and I grabbed our climbing gear and hiked into snow canyon. We found a sweet rock that had definitely not been climbed before. Climbing sandstone is a lot harder than climbing granite as we soon found out. We still had a great time and we plan on going back this spring (04). If you are only looking for climbing try nearby Zions park, but if you want unbelievable scenery topped with some great day-hikes snow canyon is your spot. The crappy thing is they wont let you backpack in and campout, they want you to stay in the "designated campground" with all the other shmucks. Plus they charge you five dollars admission plus $14 for a tent spot, per night. My advice is go to nearby gunlock reservoir and stay there for free. It isnt a very scenic place to camp, but it gets the job done. Good luck.