Can I split a pdf file?

I've looked through the documentation and searched the forums but I can't seem to find an answer to this anywhere. I have a 50mb pdf that I need to send someone but my server chokes on a file this size. Can I split this into 3 or 4 smaller files? Do I really need to buy a third-party piece of software to do this? Acrobat Pro 8; OSX10.5.1; Intel iMac. Thanks.

Jon