my site has been getting a lot of index's just by me posting on alot of forums and when i do a search for my site it shows up on alot of diffrent sites. advertiseing is the key
spiders are guests , guests are blocked from your forum - rule number one , assuming you have content
http://www.xml-sitemaps.com/ Visit that and you'll recieve a xml sitemap, they do great. i use one myself. got indexed the day after. (might be coincidence)