Having keywords in your domain name or page names is a great tactic to get better search engine rankings.
But remember, if you change your domain name or page names so you can put keywords in them, you need to use the proper redirect for both the search engines and your customers.
Otherwise you'll mess up an even more important SEO element -- you'll lose the inbound links that point to your site and help your page rank and get you traffic. So while you were trying to get better search engine rankings you end up with the short end of the stick, cursing that day you learned about &%$!@^$* search engine strategies.
You need to do a 301 redirect from your old domain name or page name to the new one. A 301 is a permanent, search engine-friendly redirect so you will not have any broken links and all the links pointing to your website will still count. The good news is your web host should be able to help you with it.
This gives you a great opportunity to name your pages something more descriptive or keyword rich, or switch to a better domain name.
Be careful, though. If your customers are very comfortable and used to your old domain name, you're probably better off to keep it as it is! Domain names that are keyword rich are great, but not a huge factor in getting top search engine rankings.
For more on redirects, I love this Wiki post on them for straightforward, useful information.
Nicole Ephgrave