Here's a sitemap generator I found in the first listings of searching:
http://www.auditmypc.com/xml-sitemap.asp
Sitemaps are mainly to help the bots get where they need to go faster. so they can see the entire site and hopefully go through and index every link. Very helpful, usually recommended.
What would keep the search bots coming is to set up your software to Ping blog serves after any new update. The ping lets those places know you've updated and sends the bots in.
If you have a good sitemap when they get there, a lot to all of your site, should get indexed.