Directory creation permission in PHP?

[Bradley Miller]

Has anyone tried to create a directory (MKDIR) in PHP?   I'm wanting this
new program I'm working on to check if a directory exists, and if it
doesn't, I want it to create it on the fly for the user.  I've tried
various examples, but I keep getting permissions errors.  If I FTP into my
site area I can create and chmod the permissinos on a directory to what I
need, but that's not exactly automated.

Any suggestions?

Thanks!

-- Bradley Miller