I am using TMO and just added some e-mail accounts through the TMO website. I tried to send an e-mail out and it worked fine but I am not receiving mails fine. I got one e-mail from one e-mail account but that e-mail account actually got four new mails and I am not getting any e-mail with my school account. Does anybody know if there is anything that possibaly might have went wrong such as setup..etc.?

Click on "advanced" when doing that setup and make sure you have the right settings for server (joe@xyz.com might not always have an POP/IMAP server that matches xyz.com). Check the port number (anti-hacking system admins sometimes pick oddball port numbers or use SSL).

P.S. Does the TMO web site show the green "check mark" logo under the word valid?

yes it does.
I added the blackberry e-mail address to my school acct so it can forward it to both my school address and my school address and now it works fine. But this also means that the blackberry cant push the e-mails from my school server.