Having a domain name that is easy to mistype or misspell is something that a huge number of webmasters have to deal with. Most just sit back and do nothing while some savvy marketers bid on the misspelling with Adwords.
There are a number of additional things you can do to make sure your brand is number 1 for common misspellings of your company name, the option you want to avoid is stuffing the incorrect spellings into your footer text in the hope that the page ranks.
Firstly you could go down the route of creating additional domains or profile pages on sites such as Netscape, Squidoo, MySpace etc. and starting the linkbuilding process in the hope that the site will rank. This seems like a lot of hard work and not a real solution.
Recently I was asked by a client about this problem and the solution we came up with was to make use of the internal anchor text on the site. We edited the navigation system to include a sitewide
link to the homepage using the misspelling as the anchor text and within a few days the page ranked number 1.
Some really clever SEO types might be thinking about the recent Google bombing algorithm stopping sites ranking from anchor text alone without having the keywords on the page. Because we had the misspelling in the navigation menu on every page, including the homepage, the site neatly bypasses this filter.