OK, so this works with a couple caveats. Apparently, Twitter doesn't allow retweeting or @mentioning with an automated hook, so you end up with the username without the @ sign, like:
"RT briandonahue: I'm working somewhere so very cool. #phillyburbworking"
Also, it only polls every 15 minutes, so there is a delay (no instant gratification for uber-connected cyber-addicts like myself).
I set it up to work with two versions of the hash tag, #phillyburbworking and #phillyburbwrkng
But, it does work, and you don't have to use the @phillyburbwrkng name at all, just the hashtag. I didnt want to retweet @replies because a lot of spammers use them, and filtering ain't easy.
To see where people are working, either follow @phillyburbwrkng or create a saved search for the above hashtags.
Enjoy!
-Brian