Have a SMF 2.0 RC 3 forum, got new URL, new SMF forum, all set up. How can I move all posts from old SMF to new SMF forum? Both are 2.0 RC 3
How do I move my SMF forum to a different host? (http://docs.simplemachines.org/index.php?topic=489.0)
Download the database from the old SMF forum,and restore it to the new one.
How do I backup my database? (http://docs.simplemachines.org/index.php?topic=492.0)
How do I restore a database backup? (http://docs.simplemachines.org/index.php?topic=490.0)
You will need to make sure your forum is connecting to the right database. You can do you by using repair_settings.php. (http://docs.simplemachines.org/index.php?topic=663.0) Also make sure to fix the paths using that tool.
edit: Arantor beat me to it. :(