If I have a forum should I include all the links in my site map ? Also in my sitemap should I also include the following: http://www.domain.com as well as http://www.domain.com/index.php Thoughts ?
Never ever include URLs with duplicate content. Infact, your website should redirect suchs URLs to one. Check this article about duplicate urls and content for more info.
Also, try to avoid 'Utility URLs' (which often contain dupe content). These are URLs that are good for your human visitors, but provide little or no SEO value... 'buy now', 'make post', 'reply', 'leave comment'. These are great for your visitors, but do nothing for you within the search engines.