I recently did a proof of concept where one part was connectivity with DB2. I had BizTalk Server 2009 developer edition installed, and thought that I would get the DB2 adapter by installing Host Integration Server 2009. Wrong! After a couple of reinstalls and troubleshooting I realized that HIS 2009 does not think BizTalk 2009 developer edition is BizTalk, and therefore the setup program hides the DB2 adapter selection. The developer version is not called Host Integration Server, but BizTalk Server 2009 Adapters for Host Systems 2.0!
Microsoft BizTalk Adapters for Host System 2.0 Developer edition is available as supplemental software to the Microsoft BizTalk Server 2009 Developer edition. See the Microsoft BizTalk Server 2009 web site for information on purchasing Microsoft BizTalk Server 2009 Developer edition. Microsoft does not offer a Microsoft Host Integration Server 2009 Developer edition. Please utilize the BAHS 2.0 Developer edition.
On MSDN subscriber downloads, you find BizTalk Adapters for Host Systems 2.0 under BizTalk Server 2009.