After waiting over 2 weeks, my Forums have finally been indexed in Google. I submitted good content to Digg and I used some Topsite/Directories to help me achieve this. Well that's one box ticked off the list!
In general it takes up to 2-8 weeks before your website will be indexed by search engines properly! However, high quality incoming links, website submission to social bookmarks, XML sitemap implemented into your website and manual website submission to search engines can really speed up this procedure!
3DProf4online is right. Since now it's already in Google index, you should attract and do some promotion to get more people to join the forum and then develop from there. More content will get the bots to crawl your forum more often.
Thanks for the tips. I was thinking of getting some Forum SEO software. I heard about vbSEO but its out of my price range. Any other alternatives?
Also, you need to monitor your forum and reply to questions yourself while it becomes popular. You need to take care of all forum visitors at the first stages and don't allow any their post to be unreplied!