From the Amnesty UK web site:
Mirza Tahir Hussain is due to be executed on 3 August. Mirza was tried and convicted of murdering a taxi driver while travelling to the village of Bhubar from Rawalpindi, Punjab Province, on 17 December 1988. The taxi driver reportedly stopped the car and produced a gun, and Mirza Tahir Hussain, who was 18 years old at the time, was reportedly physically and sexually assaulted by the taxi driver. In the scuffle that followed, the gun went off, and the taxi driver was fatally injured.
Time is short for this action but you can send an appeal on Mirza Tahir Hussain’s behalf via this handy contact form for General Musharraf. There’s even a suggested letter that you can use on Amnesty’s action page.