There are many creative ways to find alternate surname variations, but I also wanted to share an online tool that I find handy for this purpose. British Origins, one of the sites I use in my English research, employs a name search technology known as NameX. Created by Image Partners, NameX is based on a Last name thesaurus containg 75 million entries for 1.5 million distinct last names and a First name thesaurus containing over 3 million entries for 260,000 distinct first names. This generally results in fewer, more accurate name variants than Soundex. For example, while NameX identifies 21 highly plausible variants for the surname Owens, Soundex identifies 659 "variants," of which nearly 90% are extremely unlikely (eg. Oyoumick, Ounnoughi, Onehawk). NameX does miss a few likely ones, of course, such as Owins, but it also provides a much more reasonable number of surnames to wade through than Soundex.
I find the First Name Thesaurus to be of particular help, since Soundex doesn't address this, and many genealogy databases don't offer anything other than wildcard searching for first names. A search for Kimberly brings up some great variations, including Kim, Kimberley, Kymberly and Kimberlee.
The NameX name matching technology is sold to companies, but the Surname Thesaurus (which includes a Forename Thesaurus) is available on the Web, and can be freely accessed for personal use. A great resource the next time you need some help getting your creative juices flowing!