Microsoft have recently jointly released the Citrix connector for ConfigMgr 2007. Through this release, the ConfigMgr SDK has been used to extend and support the management of application services through XenApp. Very cool indeed.
Here is the announcement. Links are below.
Citrix® XenApp™ 6 introduces integration with Microsoft System Center Configuration Manager 2007 R2 giving organizations a single, integrated view and management of all applications across the enterprise including on-demand apps by XenApp. The Citrix XenApp Connector leverages the Configuration Manager console to deploy and publish applications and updates to XenApp servers with zero disruption to users and extends the reach of Configuration Manager applications to a broader set of users, devices and access scenarios
Some resources for you: