There are some good tips on monster.co.uk and the other job sites such as
www.jobsite.co.uk and
www.reed.co.uk
Do write it yourself. Get other people to check it - don't undersell yourself and don't use jargon. I use linkedin.com to hold my online profile and recommendations - a lot of recruiters are using this now - you can get an account for free (PM me if you want an invite) - I have a link to this on my two page CV. If people are interested, then they can find more by clicking on the link.
Probably worth getting a copy of What Color is Your Parachute from WH Smiths - lot of job hunting and career review tips in there.
DON'T use a professional CV writing service. I did a couple of years ago - cost a few hundred pounds and what I got was a bunch of cliches that did not speak for me. If I see a CV I expect that it comes from someone who is able to express himself in clear and concise English. If they can't, then what use are they going to be as an employee?
Good luck!