From what I saw of the construction last year, it's next to and behind the Land attraction. That would put it on the opposite side of Future World from Test Track.
The line for Soarin is inside the Land pavillion where the Food Rocks use to be. The addition to the building can be seen between the Land and Journey to imagination, it's sky blue. Soarin' was great, we did it passholder preview weekend.
Went to Epcot yesterday hoping to do Soarin'. At Epcot arrival around 10:15 saw on information board that Soarin' was open for previews. Walked over to the Land and into Soarin' area and into attraction. There were around 50 people in line at that time. From that point took around 10-15 minutes of wait time before got to ride. Checked around 5:00 in the afternoon and wait time was 2 hours with no fast pass tix left.
I'd say about 10 minutes or so, depending on how fast you walk. Go past the UK and Canada, take the shortcut path thru the rose garden and past the Imagination pavilion and you're there!