If you feel like listening to Thanissaro Bhikkhu talk for about 6 hours, he has a very long (multi part, of course) talk on Emptiness from the Theravada perspective; http://audiodharma.org/talks/ThanissaroBhikkhu.html
There is also a shorter 1 hour version - but the 6 hour one covers a LOT of territory, including the Mahayana perspective. Or, probably better said, a Theravadans perspective of the Mahayana perspective. The Theravada bias is apparent, but understandable.
An article of his is here --> http://www.accesstoinsight.org/lib/auth ... iness.html
which covers a lot of the same territory, but doesn't go into the whole Nagarjuna/Mahayana etc. thing.
Personally, if I'm talking to a mahayanist or zennie friend, I just set my internal mental babelfish to translate it to "anicca, anatta, dukkha" and the conversation tends to progress pretty smoothly. "The Five Skhandas are Empty" (per the heart sutra) translates to "The Five Khandas are anicca, anatta, dukkha" which is absolutely true. When it gets sticky is when people want to talk about this myserious animal called "reality," at which point I try to quietly back out of the conversation, since the only realities I'm concerned with are dukkha and the cessation of dukkha.