Re: the unit shown. While the window can be replaced, it is *NOT* an easy task for many reasons.
It is the later halfnuts that have an integrated LCD/Keyboard/Proceesor in which the window cannot be replaced without serious surgery. That work will leave you with a less than perfect result.
The unit shown is a fullnut in which the LCD can be removed as a seperate module.
Once the LCD has been desoldered and removed, the window can be removed from the back. It is made of 1/16" thick injection molded crystal polystrene and is somewhat brittle which is why they crack. If the old one doesn't snap out cleanly, you've got a mess on your hands. Making an exact replacement is almost impossible by hand, the easiest method is to salvage one from an otherwise dead unit. Installing can be tricky without doing cosmetic damage.
IMO, unless it sells for $5 and the crack doesn't bother you, save your money.
Edited: 23 Aug 2006, 3:40 p.m.