Can anybody help me with *any* information on MMOG (Massive Multiplayer Online Gaming) engine development ?

I'm trying to develop simple (as a start point) MMOG engine using PHP + MySQL (or PostgreeSQL). Main questions are:

0. Is it necessary to put game logic on DB triggers and stored procedures ?

1. Can Apache's 1.3.x (or 2.x ???) build-in multithreading support be used to serve, say, 1000 users simultaneously ?

2. What are the mechanisms of collision evasion when two or more users trying to access the same game resource (say, building) ?

3. The main idea is to use Flash (Macromedia) client to control game process, which runs in real-time. So the problem is to process all commands from almost army :confused: of users. Can that command processor be made without threads usage ?

Thenx a lot for any info...