Fly into Kalispell, drive through Glacier National Park to the east side, take the road into Many Glacier area, and park at the Many Glacier Lodge. Take the boat at the Many Glacier Lodge to the trail head, then hike up 3 miles to the glacier and lake. Or instead of taking the boat, park at the trailhead just west of the lodge entrance, and add 2.5 miles to the hike through forest and along the lakes.
This is a very popular hike - plan and book ahead. The area at the end of the trail is huge, so don't be dismayed by the volume of hikers.
Third time up the trail to Grinnell Glacier in Glacier National Park and this time around was actually able to capture some decent images. I particularly like this one as the multi-faceted rock reflects the power of the remaining glacier and cliffs in the background.