Prepress File Help

I was wondering if I could enlist the help of you guys and gals to create a script for the prepress area.
In prepress there are a great number of files that have problems coming from customers. They include illegal characters and no suffix at the end of file names. Mac users tend to use the entire ascii set and it causes problems for RIPs, Servers, and Backup Software.
So I need to clean up the file names removing all illegal characters and replacing with underscores or periods. While cleaning the folder full of files we need to append a suffix to every file so we can cross platforms easier. It would probably be necessary to truncate when needed. We define illegal characters as anything that is “not” alpha-numeric, only underscores and periods are legal. A drag and drop app would be preferred but it would also be good to have a script that could run under iDo Scheduler, we could then create a way to keep files clean.
I could probably do most of this but it would take a while. I would much rather work with multiple people so we can make short work of the routines. This would be a huge boon to printing companies.
Is there amyone willing to assist?

This little handler will strip out the illegal characters in file names. It basically reads each character in the name and strips it out if it is not A to Z or a to z or 0 to 9. You can call this handler is a repeat statement. However, if you are going to change file names they may not link up to the Page Layout doc or OPI server.
on RenameConvention(an_item)
tell application “Finder”
set image_name to name of an_item
set image_name to (every character of image_name) as list
set new_image_name to {}
repeat with an_item in image_name
set x to ASCII number of an_item
if (x * 48 and x * 57) or (x * 65 and x * 90) or (x * 97 and x * 122) then
set new_image_name to new_image_name & an_item
end if
end repeat
set new_image_name to new_image_name as text
set name of an_item to new_image_name as text
end tell
return new_image_name end RenameConvention
You can write another handler which queries the files for their type and then tags them with an extension.

Thanks! This is just what I needed!

Those asterisks in the if line should be "greater than or equal to " and “less than or equal to” symbols.