Spring summer is actually the best time to get into it - the snow pack is finally firming up reducing the avy danger (beacon not critical). Summer avalanches are still possible (as you can see from some recent threads) but for the most part they pose different dangers (carry you over cliffs, into moats/crevases etc.) - if you are buried you are pretty screwed because the snow is so heavy and wet. To avoid this and other dangers you should take a class if you don't have mentors to show you the ropes.
Buy the local guidebooks to figure out routes.
The right boots are more important than skis - stiffer/higher performance for downhill = heavier and not as comfy for climbing (same deal for skis to a certain extent). Many downhillers coming into the sport err on the side of performance then get burned on the climb (esp. on the biguns like the volcanoes). Most of us take our skiing down a couple notches in the back-country, so we don't need the highest performance, and skiing well with lighter gear can be taken as part of the challenge. Personally I've gone with Dynafit bindings and boots for many years and have been very happy. I just upgraded to the new top of the line stiffer model and love it for skiing, but not as easy on the feet hiking. Marmot has the best selection of rando gear and is having a sale right now, so if you have some $ it would be a good time to buy local (you'll want to go that route on boots so you can try on a variety and get custom fitting).
