Parallels has released an update for Parallels Desktop for Mac.

In case you missed it, Parallels Desktop for Mac lets users run Windows and other operating systems at the same time as OS X on any Intel-powered Mac, without re-booting.

Update Release Candidate (RC) for Parallels Desktop for Mac is free for all Parallels Desktop users. It adds support for the recently released quad-processor (Xeon) Mac Pro. It is now compatible with all current Intel Macs.

The update also introduces full compatibility with the developer builds of Mac OS X 10.5, code-named 'Leopard'.

"By adding support for Mac Pro towers and OS X Leopard, we've shown once again that Parallels Desktop is not only a great productivity tool for any Intel-Mac user, but also for Mac software developers who need to work with Apple's next-generation OS," said Benjamin Rudolph, marketing manager, Parallels.

The software also introduces beta support for the Windows Vista beta.

Additional improvements include:

- Solaris guest OS no longer hangs after suspend/resume
- An improved Parallels Tools package
- Full support for OpenBSD 3.8 as a guest OS
- G4U hard disk cloning tool now works in virtual machines.

Installing the update does not require the guest OS to be re-installed, though they should re-install Parallels Tools after the upgrade. The final release of the upgrade is expected in the next few weeks.

A 15-day free trial version of Parallels Desktop is available from the company. The full version presently costs $79.99.