I'm going to have to agree to the first response, the Validator is one of the best ways to go.
Having someone experienced go through manually will be a plus though, as there are a lot of errors that Validation alone will overlook (such as unnecessary even though 'properly' written code.)
As far as hosting and whatnot, I'm going to recommend two webhosting companies owned by friends of mine..
1)
Surnaturelle.net - is owned by a friend of mine of several years, she's got a lot of clients and does a very good job at keeping them happy. The server is her own though managed by a relative company, very fast and I haven't seen any problems with them.
Her cheapest package is 50 MB of storage space, and 1 GB of bandwidth at $13.50 (USD) a year with a domain (com,net,org) or $5.50 a year without.
2)
Tehlove.org - Cheaper than Surnaturelle, the servers are very reliable (I've been a reseller with the same company she uses, so I definitely know), her service is very fast (I have a domain hosted by her).
Her cheapest plan is 350 MB of space, and 6 GB of bandwidth at $15 (USD) a year, including a free domain registration (com,net,org).
Both offer Cpanel and Fantastico, and both will do custom plans if you'd like.
Wow, I sound like an advertisement. Hope this helps at all.