My daughter got the hint when she watched "Elmo Potty" DVD - as she loves Sesame Street.
When I felt she was ready, I made a big deal in letting her buy underwear, put it on (just like Prairie Dawn in the DVD!) and put a pull-up over the underwear - so she feels wet AND the pull-up catches the accidents. When she had an accident, I would say -"oohh no!!!" and put it in the laundry. She poo-pooed in her underwear ONCE because there was no way I was going to wash it out and she became SO upset that I had to throw away her FAVORITE underwear!! So, that stopped...
I think potty training is all about communication too...so keep at it - he'll eventually get the point!! :)
Another option I did in the beginning was have her run outside with NO diaper and nothing on her bottom - just a dress. I watched her carefully ALL day. If I noticed she had to pee - I put her on the potty. I laughed so because she HAD to go, and realized she had no diaper - and she had this confused look on her face. She refused the potty and instead, HELD it in! When it was naptime, I put the pullup on and then she went!! Same thing happened after nap time. It didn't work then, but it got the point across that diapers were "all gone" and we were trying something new...then I did the underwear/pull up thing and praised her when did did it!!
Also, pick one strategy and be consistent for some time...I know if one day, it doesn't work, it's tempting to try something else the next day - I wouldn't change the strategy in one day though...consistency helps.
:) Good luck!!!