PHP code critique

I'm new to PHP. I have been heavily modifying a webmail POP client written in PHP by someone else for my use. Anyway, I wrote the following administration script from scratch and if someone has time to critique my code that would be great. If I'm doing anything majorly wrong I'd like to know before it becomes a habit. (The code works fine, I'm talking about style and implementation issues). Also, if you click on the "Expand" button to expand the view, the database code is pretty slow to execute (of course). If I'm doing anything majorly slow there let me know, I'd appreciate the pointer! :) (The reason for the HASH table is because SHOW TABLES in MySQL is rudimentary compared to a SELECT and does not sort the same way as the SELECTS do. I have to get the data from that into a format that I can SELECT with. Maybe an ARRAY in PHP would be faster?). Thanks, Matthew Source Code: http://www.symatec-computer.com/_tmp/index.php.txt