Research In Motion (RIM) will let developers create applications for BlackBerry phones using Microsoft's .Net programming environment, continuing its efforts to broaden the capabilities of the devices.

The BlackBerry plug-in for Microsoft Visual Studio lets developers write applications that integrate with existing back-end servers through .Net Web Services, RIM said Monday. The plug-in works with the BlackBerry Mobile Data System.

The new support will open up the BlackBerry developer community to include .Net developers and could make it easier for enterprise developers to build new mobile applications for workers.

While the BlackBerry for many years was mainly a mobile e-mail device, RIM has increasingly enabled more capabilities for developing other wireless applications as it faces growing competition from companies such as Microsoft and its Windows Mobile operating system.

For example, RIM offers the Mobile Data System, an application development framework for enterprise BlackBerry users. Customers use the MDS to build applications that allow mobile workers to access standard enterprise applications from companies like SAP.

In late 2005, RIM added support for Web services but that didn't include the .Net framework.

RIM also enables a Java development environment that allows developers to use Java to build applications for the BlackBerry.

The application development support from RIM may help it hang on to existing customers and attract new ones in the face of Windows Mobile competition. Windows Mobile devices can receive push e-mail from Microsoft Exchange, which many companies already use for PC-based e-mail. By contrast, enterprise customers must buy and support a separate server from RIM in order to push e-mail out to BlackBerry users. Support for more applications than just e-mail may make the extra server more attractive to enterprise customers.

RIM will make the plug-in for Visual Studio available for free later this year.