You should be able to access SharePoint content if you have the MDS-CS component enabled and support HTTP authentication enabled (if you require authentication to your SharePoint site). MDS-CS is what provides the pipeline back to your LAN from the blackberry. Browsing SharePoint from your blackberry won't be much different then from your windows mobile phone. You won't be able to do much more than actually read a site.
There are third party applications that give you full access to your SharePoint content, such as SilverDust, which support a range of features like calender intergration, workflow, document checkin/out/edit among many others. There is a link to SilverDust available in my signature.
Disclaimer: I do work for the company that provides SilverDust