Will Writing Resources
The BBC have produced a nice page on how to make will writing fun.
Wikipedia's page on will writing
As ever, bear in mind that this is Wikipedia and therefore cannot be seen as 100% gospel. Also note that the information is quite generic and not UK-specific.
Plenty of great advice and info on this site. Probate is the court's authority to divide your possessions after your death.
DirectGov Wills & Probate section
More official government information on will writing and your legal rights. A great information resource.
Great resource for tracking British and Irish genealogy.