Stalled Fermentation

I brewed a Bend Hop-Head Imperial IPA clone last weekend and had an OG of 1.068 and pitched 2 packets of Wyeast 1968. On Wednesday, I took a reading and it was 1.020 at 73 degrees, then today I took another reading and it was at 1.020 at 67.5 degrees. I dry hopped 1.5 oz of cascade hopes as well. I did not rack into a secondary.

My questions, is my fermentation stalled? If so how would you suggest getting it unstuck and going again?

That's 70% attenuation, which is fairly normal actually, especially for English strains. I bet it's just done, but you could always do a forced fermentation test (http://braukaiser.com/wiki/index.php?title=Fast_Ferment_Test) to see for sure. Otherwise, if you want to post more details about your recipe and process, we can see if anything stands out.

1.068 to 1.020 is 6.4% ABV. That's about 70% attenuation. Wyeast 1968 is listed as 67%-71% attenuation. It sounds like it's not really stuck so much as finished.