With the release of Pro Tools LE 5.1, sessions are transferable between Mac and Windows systems. For more information, see page 107 of the Pro Tools 5.1 Reference Guide available from the "Help" menu in Pro Tools LE.

How to create a cross platform session:
* Since Pro Tools 5.1 is the first to support cross platform functionality, both systems must be using Pro Tools 5.1 (or later) to make this possible.
* Open the desired session(s) on the original system.
* Choose File>Save Session Copy In...
* Choose either AIFF or WAV for the Audio File Type
* Enable the "Enforce Mac/PC Compatibility" option
In Pro Tools 5.0.1 on the Windows platform, you can bring your Windows 98 SE Pro Tools LE sessions to a Windows NT TDM system, and bring Windows NT TDM sessions back to Windows 98 SE Pro Tools LE. The same integration Between LE/TDM is also possible on the Macintosh Platform. True cross platform support for Macintosh and Windows 98 SE Pro Tools LE requires Pro Tools LE 5.1 or higher.