Getting ready for Friday's launch is STS-134, the Shuttle Endeavour.
As reported by pjm on twitter, comms have been heard on 261.575 for the Shuttle support missions. These forward deploy from Europe to the Shuttle TAL sites.
On launch day you will hear HERKY callsigns working DoD Cape via SATCOM for radiochecks. This is usually all you hear on SATCOM before launch, but it's worth keeping an ear out on 261.575 and others.
After launch, keep 259.700 plumbed into your radio, preferably in AM mode. The shuttle talks to Houston on this channel until they're established on a good trajectory and are able to use S-band to downlink via satellites. The S-band links are beyond my station's capabilties, but the genius Paul and others on #hearsat have and do decode them. Check out http://www.uhf-satcom.com for more info on that.
The guys at Mysteryship have received and recorded some pre-launch TAL activity on the Fleetsatcom-8 transponders, 261.550 and 261.575. Take a look http://home.tiscali.nl/mysteryship/spaceshuttle/sts134.html for their captures.