The latest version of BizTalk is BizTalk Server 2009 and IDE to develop application is Visual Studio 2008 SP1.
Top New Features
BizTalk Server 2009 introduces enhancements and new featured in four main areas:
Updated Platform Support
Support for Visual Studio 2008 SP1
Support for .NET Framework 3.5 SP1
Support for Windows Server 2008
Virtualization support with Hyper-V
Support for SQL Server 2008
Developer & Team Productivity
New Application Lifecycle Management (ALM) experience - with Support for TFS - integrated source control, bug tracking, unit testing, MSBuild automation
Enhanced Developer Productivity with Visual Studio project system updates & Map Debugging
SOA and Web Services
ESB Guidance 2.0
New UDDI v3 Web Services Registry
New and enhanced LOB adapters (Oracle eBusiness Suite, SQL Server)
Enhanced host systems integration (WebSphere MQ, CICS, IMS)
Enhanced BAM support
Business to Business Integration
New Mobile RFID Platform
New RFID device management and industry standards support
Enhanced Support for EDI and AS2 Protocols and Drummond certification
Updated SWIFT Support and SWIFTReady Financial EAI Gold certification
Please refer to http://www.microsoft.com/biztalk/en/us/whats-new.aspx