I may have found a work-around for the unresponsive trackpad after sleep issue in Vista. I use the Apple driver (manual install as pr this thread).
Work-around: Locate and download DevCon.exe from Microsoft.com. It is a utility for performing device management from the command line. In my case I saved devcon.exe to %SYSTEMDIR%. Create a task in Task Scheduler with trigger "On an event". Log: System, Source: Power-Troubleshooter, Eventid: 1. You need two actions: Start a program: Devcon.exe. Parameters: disable "USB\VID_05AC&PID_0218&REV_0060&MI_01" and Start a program: devcon.exe. Parameters: enable "USB\VID_05AC&PID_0218&REV_0060&MI_01".
The hardware ID of your trackpad may be different than mine, so you must check it and copy it from Device manager.
The task should run with "highest privileges" (to avoid User Account Control messing things up) and it must be able to run any time.
A rather clumsy solution, but its the best I can do...