Astronaut and scout master Mike Fossum is planning to participate in JOTA from the International Space Station. His schedule is somewhat flexible on the weekends but will not be available for every pass.
The typical crew work periods are 0800-1930 UTC but they are sometimes available a bit later.
Check to see if the ISS will be passing over your area during that time period.
When available, Mike will be listening on the ITU Region 1 (Europe, Russia and Africa) uplink of 145.20 MHz and ITU regions 2 & 3 (everywhere else) will use the uplink of 144.49 MHz. He will be using the call sign NA1SS.
Worldwide downlink (where he transmits) is 145.80 MHz.
(Thanks Kenneth Ranson at NASA).
Picture 2: A helmet view from astronaut Mike Fossum after the July 12, 2011 installation of the Robotic Refueling Mission on a temporary platform on the International Space Station. From flickr