Red Hat's Mike A. Harries has posted a workaround for the Synaptics touchpad/Kernel 2.6.x issue

I've noticed a fair number of people lately who have been testing the 2.6.x kernel on laptops, reporting they are unable to use their laptop's touchpad anymore.

This is a known issue which is related to ACPI. If you have one of these touchpads, and it does not work (most or all of them wont work), then currently you have to download a separate GPL licensed "synaptics" driver from the following website:

Read more