I'm working on creating a Forum program in PHP, and I'm trying to figure out how to setup the database. Should I have:

Two Tables: threads and posts (replies). Threads would contain the original (1st post) of the forum, and posts have all the replies. Like:

threads: id, title, ...
posts: id, title, ..., threadID

One Table: one table for threads and posts (replies). All are stored in one thread. But how to tell which is a thread starter and which is a reply, then how to tell which reply goes with which thread

Many Tables: 2 tables for each forum. like forum1 and forum1r, forum2 and forum2r. So like "General VB" would be forum1 and the replies would go in forum1r. "Chit Chat" would be forum2 and the replies would go in forum2r.

Or...what? I'm open to ideas on this as I have no idea how to setup the databases.