Welcome to WebmasterWorld cirlong!
Don't worry about being new to this, we were all new at one point.
Before you start submitting a sitemap it might be helpful if you ask yourself why you are doing it? Sitemaps can help increase the indexing of your site. If you are trying to get your pages to rank better, you should probably focus on link development and the uniqueness of your content instead.
You do not have to list all of your URLs in the sitemap. I rarely submit a sitemap and when I do submit a sitemap I include my tier 1 pages, maybe tier 2 and skip tier 3 (each tier level is based on how important that page is to me). In case you are wondering why I rarely submit sitemaps, that is because I spend alot of time working on the internal linking. Google loves to follow internal links. If you have good enough linking then you can avoid the need for a sitemap. (PS dont forget to get inbound links from external sites)
If you do want to submit all of your URLs and think that it will create too large a file you can break the sitemap up into multiple files, for example one sitemap for each subdirectory.
As for a tool to create the sitemap there are many third party tools that you can use. Just do a search for them. Google even provides a tool (http://www.google.com/support/webmasters/bin/answer.py?answer=34634).
Congratulations on your new site and good luck