Solution for Lexmark/Leopard crashes..
Make sure you have printer software and drivers installed.
Open *System Preferences > Print and Fax > Options and Supplies > Driver > Print Using* : +select a driver to use+ - select *Generic PCL LaserPrinter* *> OK*
Now print a document using the offending application, immediately after hitting Print pause the printing in the printer queue (use the printer icon which has now appeared in the dock). With this panel open hit *Info > Driver > Print Using* : +select a driver to use+- select your printers driver eg.*Lexmark x5400 > OK > Resume*
The document should now print as normal,for me, I have not had to redo these steps,it just seems to work,see how you get on, it may only be teporary until Lexmark come up with a solution.
PS. this would probably work with other printer manufacturers too, but I haven't tried yet!
powerbook G4, Mac OS X (10.5)