Here's one small tip that can make your life a little bit easier when developing on BizTalk Server: Reduce the cache refresh time.
Many developers get sometimes frustrated when they make a change to their BizTalk configuration (such as changing the pipeline used by a send port) and BizTalk does not seem to pick it up. They will waste valuable seconds (minutes in some cases) restarting their BizTalk Hosts trying to get it to pick up any changes. This makes life harder than it needs to be.
The reason this happens is that to improve performance, BizTalk will cache in memory a lot of the configuration settings. This cache is only refreshed periodically, so configuration changes do not take effect right away, but only when the cache is refreshed. By default, the cache refreshes every 60 seconds, which is enough to ensure performance is decent, but long enough to give the developer the impression that BizTalk is not picking up his changes and thinking it requires a restart to do so.
Fortunately, you can change the configuration cache refresh rate pretty easily from the BizTalk Administration Console (both in 2006 and 2004). Expand the node for your BizTalk group, right click on it and select the Properties option from the popup menu. You'll find the cache refresh option there (the dialog is a little bit different in BizTalk 2004, but the option is there alright).
I usually change it to 5-10 seconds on my development machines, which for all purposes makes it seem like the configuration options indeed happened instantaneously.