9.1 million people search every month for SEO related content, that's a huge marketplace that will grow for years to come, part of the SEO firms appeal is that they can really help small businesses to rank highly and find new customers, they can compete with large firms for market share and they can actually win some customers away using the internet.
WIth small businesses going through difficult times in the recent recession we can now be sure that SEO can still deliver the most cost effective marketing solution to many startups and small businesses, we find that as the internet becomes more and more mainstream this return on investment will only grow larger.
SEO is the perfect marketing strategy for just about any small business, it's cost effective, easy to measure and one of the most difficult things to get right, this means that most of your competitors can't enter the same channel which makes it much easier for you to dominate.
Since there are alot of seo firms out there these days its always best to go local with your searches so for example if you wanted an SEO firm in hartlepool you'd look at Rent Sites if you wanted one for london you could look at Go Up or if you just wanted general information on SEO then this Wikipedia page is really helpful.