Polycounter Leslie Van den Broeck (Ravenslayer) has released a new and improved version of his popular Grabviewport script for 3ds Max. This script allows you to capture high resolution screenshots straight from the viewport, as well as animations. You can also capture multiple passes for compositing.
Check out the thread and grab the script here: http://www.polycount.com/forum/showthread.php?t=92812
A big thanks to Leslie for putting this together for the community.