MySQL Optimisation

I am looking for someone with knowledge of MySQL optimisation techniques to help us improve the performance of a well trafficed ecommerce site. The site is written in ASP and suffers from "sticking" occasionally. Looking at the various server performance tools, the mysql process often spikes cpu usage hitting 50% or more cpu briefly It also appears to be making a large number of disk read/writes I think it may be simply a case of creating some appropriate indexes and possibly reviewing a number of slow quieries, possibly suggesting better sql quieries or another approach to getting or caching the require data. Ideally I'd like the applicant to come to our offices in Newquay, Cornwall and spend a day with us reviewing the system, helping us implement any changes needed etc