BizTalk Server provides a few out of the box pipeline components. For instance the S/MIME components for encrypting or decrypting messages. In case you need to do some pre- or post processing on a message and the functionality is not offered through the
provided pipeline components you will need to built your own custom pipeline component. However there are quite a few available customized pipeline components available you can reuse and save you the time of building it yourself. This article provides you
as developer all the resource available regarding custom pipeline components for BizTalk Server.
Another important place to find a huge amount of BizTalk related articles is the TechNet Wiki itself. The best entry point is
BizTalk Server Resources on the TechNet Wiki.