I have Apache with SSL and PHP support running in a chrooted environment on my web box. I am also running Squirrelmail from within the chroot jail. I am not, however, running courier-imap, fetchmail, or procmail in any jailed environment. Does running a mix of programs (in and out of the jail) that coordinate together compromise the security measure of a chrooted jail? Should I try to get courier-imap, fetchmail, and procmail all to run within that same jail?

Also, I've heard that a chroot should be an entirely seperate partition altogether. Is this true?

Well did you TEST all functionality? Like can you still use PHP's mail function? Do MySQL connects work? Are you also using perl? Which Apache and PHP version are you using? What software did you install in the chroot for forwarding mail?
Well you can think of a jail as a directory subtree. The more you install in this subtree the more you loose security. Remember the benefits of a chroot: minimum access to software, etc. If however you have a LOT of software within the chroot you loose system security.

Applications can cooperate fine if they are partly in chrooted environments. If you have set up those chroots correctly then it will be no problem at all ... you shouldn't notice anything at least :-)

Running fetchmail chrooted? Well that makes no sense to me honestly, except you poll all the time (which would make fetchmail a daemon in that way). Regarding chrooting courier-imap you have to think of the mail directory for that user and the authentification ...
It's good practice ...

I can use Squirrelmail flawlessly. I compliled PHP without MySQL support. It was not needed for just using Squirrelmail I don't use anything for forwarding mail in the chroot. I have created home directories under the chroot to store mail in. Btw, how can I tell that everything is running truelly within the chroot?

Very good point. Answered my question.

get the process id of your daemon (httpd), ls -l /proc/<pid>/

Example:

What output should it have, and what shouldn't it? Should the absolute path show, or the chrooted path? IE, if apache is chrooted in /var/apache, then should the processes show '/var/apache/bin/httpd' or '/bin/httpd' ?

EDIT:
# ls -l /proc/1296
total 0
-r--r--r-- 1 root root 0 May 29 16:32 cmdline
lrwxrwxrwx 1 root root 0 May 29 16:32 cwd -> /var/export/chroots/www4
-r-------- 1 root root 0 May 29 16:32 environ
lrwxrwxrwx 1 root root 0 May 29 16:32 exe -> /var/export/chroots/www4/apache/bin/httpd
dr-x------ 2 root root 0 May 29 16:32 fd
-r--r--r-- 1 root root 0 May 29 16:32 maps
-rw------- 1 root root 0 May 29 16:32 mem
-r--r--r-- 1 root root 0 May 29 16:32 mounts
lrwxrwxrwx 1 root root 0 May 29 16:32 root -> /var/export/chroots/www4
-r--r--r-- 1 root root 0 May 29 16:32 stat
-r--r--r-- 1 root root 0 May 29 16:32 statm
-r--r--r-- 1 root root 0 May 29 16:32 status


So far all the apache processes show this. Does it appear to be chrooted fully?