The hackfest is going to happen from 14th to 18th April in Boston (MA, USA). We haven't agreed yet on a venue, but we are aiming for something near Kendall Square.
We'll be 3 people working on Python 3 support, and 3 more on the introspection bindings. More details at http://live.gnome.org/Hackfests/Python2010.
The GNOME Foundation will be sponsoring the travel, an as-of-yet unnamed sponsor will be providing the venue and the GNOME Foundation board is busy looking for sponsors for hacking food and such.