Actually, someone pointed out that Google has a calculator where if you type "inch to cm" it will show up with the answer. The fact that I didn't discover that but I did happen upon the Windows Live search version, just proves that Live Search must be easier to use ;-)
On a subnote, though - both allow you to put numbers in there too... so in Live Search if you enter "6 ft m" it will tell you that 6 feet = 1.8288 metres ...