I like to setup appointments for conference calls so that the "Location" field of the appointment has the phone number AND the passcode formatted so that the Blackberry waits for me to press a key to send the passcode.
Here's what I do:
800-123-9876 x1234567890# 123-456-7890
The "x" seems to be the magic that makes the Blackberry wait to submit the "extension" number. And I think the "#" is needed (not sure about that).

The problem is that the passcode has to be a continuous string of numbers. If I punctuate it for readability, only the numbers before the first punctuation "-" are sent. So I add the passcode after the # to make it easily readable (especially when Outlook pops up the reminder on my PC.)

I can't even remember where I learned about the "x" and the "#". Any help on this would be appreciated.

last one a joined in was like this

123-456-7890 - 972819158
old one like this
123-456-7890x12345678

Not sure of the pound sign usage

The x tells the BlackBerry phone that an extension follows, so you are making use of that feature to automatically enter the conference code.

Have you looked at the free BlackBerry Mobile Conferencing app? It may make things easier for you.

I second this.