Lease it to them with an option to buy.
Domains like that are hard to value - on the surface it's not that great of a domain and I wouldn't think it gets many type ins per month
That said, it could be a good domain for anyone who's building a chat network and is attempting to gather as many relative domains as possible. You'd hate yourself if you sold it for 6K now - only to find out the buyer was a representative of Google and 1.5 years from now broadtalk.com is their flagship domain for an incredibly large network
