Kittens get vaccinated from the age of 9 weeks in the UK, i'm not sure on the microchipping though?, but the new kitten i'm getting at the weekend i was planning on getting him chipped when he goes in to be neutered
9 weeks for both vaccinations and microchip (with 2nd set of vaccinations at 12 weeks), or they can do the microchip while your cat is anaesthetised for neutering - many vets offer a 'chip and snip' package
I've done it both ways - Radar had the 'chip and snip' at 6 months old, and Sonic was chipped by his breeder's vet when he had his vaccinations. I don't honestly think it matters, the needle looks big but it's all over and done with in the blink of an eye and they don't make any more fuss about it than they do with the vaccinations. I'd ask your vet what he suggests
ETA: for neutering, most vets in the UK won't do it before 5 to 6 months, but it's best to get it done as young as possible, before they start spraying or going into heat if at all possible. Basically just get it done as soon as your vet will do it! If your vet does them younger than that you are lucky and should take advantage of that