Geez! I'm a day late.
The general consensus is that a SATA 3 ssd is backward compatible with a SATA 1 motherboard. It should work, providing certain conditions are met. SSD performance will be restricted to SATA 1 levels but it should still be a noticeable improvement compared to a hard disk drive.
Here is a link to an installation guide which might prove useful:
http://www.pcadvisor.co.uk/how-to/laptop/how-upgrade-your-laptop-hard-disk-ssd-3366618/