One of the requirements for BizTalk 2006 is that you must use Visual Studio 2005 for development. This makes sense because everything in BizTalk is now based on the .Net 2.0 Framework. Microsoft has made a few modifications for the developer on this from.
If you look at the Properties of your BizTalk Project, you now have a couple of new options (You can right click your project, select properties and then navigate to Configuration Properties, Deployment). You can now enter an Application Name which is a new feature of BizTalk 2006. If you do not enter a name, it will use the default application (which defaults to BizTalk Application 1). In this dialog window, you can also specify Redeploy = True (which actually works this time) and you can also specify to restart Host Instances upon deployment. This really can help speed up your development time.
For Redeployment, you may have a scenario where you have a Schemas Project, Maps Project and an Orchestrations Project. If you have everything deployed and you make a modification to a Schema in the Schemas Project, you can right click and specify Deploy. The Tool will now take care of Undeploying the assemblies that rely on the Schemas Project (in this case the Maps and Orchestrations projects) and the new Schemas Project will be deployed. This will not redeploy the Maps and Orchestrations Projects! This saves you from having to undeploy everything by hand, but you will still have to go in and redeploy the projects that contained a dependency to the schemas.
Visual Studio 2005 has the same BizTalk Explorer as we had in BizTalk 2004. If you use Visual Studio to create a Receive Port/Location or a Send Port, it will only look at the default application. This can cause issues or confusion if you don’t realize what is going on. If you specify an Application Name for your project and deploy, a new Application will get created for you. If you then add a Send/Receive Port from within Visual Studio, it will not be using your new Application, but the default application of BizTalk Application 1. You will need to open the BizTalk Admin Tool and move your Send/Receive Ports from BizTalk Application 1 to your new Application. There is not much pain in doing this, but you just need to be aware of it.
To ease this process, you can Create and Deploy your Application via Visual Studio. Then you can open the BizTalk Admin Tool and change the default Application from BizTalk Application 1 to your new project. You can right click your Application and select Properties. There is a checkbox that states: Make this the default application. Now the BizTalk Explorer in Visual Studio will be pointing to your new Application and all is well.
These are just some basic changes in BizTalk 2006, but they really help out with the development process.