yes, a client of mine was contacted by a firstfound telemarketer and i then had a chat with a guy from firstfound. they told me their methods and i say they're basic methods and will produce basic results. i am not ghastily unimpressed but i could produce better results than them for 10% of what they charge. but that's not to say that the average seo company is any better.
clue yourself up on seo here:
...and don't forget to ask how much they will charge you on condition that you don't have to link to them from your site (which is actually using your popularity to boost theirs!)