The Summit of Snoqualmie Mountain is actually the border of the Alpine Lakes Wilderness in this area. Any camping north of the summit (such as towards the thunder creek drainage or the commonwealth basin area) is allowed and subject to the Alpine Lakes wilderness camping rules. South of the peak (towards the ski area) is just plain ol' national forest, so Scott's suggestion of checking with the ranger is a good one. I'm not sure why you'd want to camp on the south face of Snoqualmie Peak, however. :-)
