Well, if I was you, I'd try and avoid anybody who will offer you #1 rankings guarenteed. SEO is a rather long, labourious process (I hit #1 for a keyword I was targetting today though, so go me!), and should be done with this in mind.
However, if you show us a website you want SEO'ing, I'm sure a few kind souls could give you a starting block for where you can continue from
