I've outlined elsewhere my suggestion for a pdf based/http upload style mobile printing solution.
The only problem is that microsoft word does not natively support pdf export, which means installing something like CutePDF on students pc's, or alternatively getting them to use Open Office, which does do native pdf export.
Both are bad things as they involve students hving to install software on their (own) pc's. This is generally a bad thing as we end up having to field version incompatibilities, general incompetence, and "open office ate my thesis" excuses.
However open office can be driven in command line mode so the answer might well be to provide a service that takes the input files and converts them to pdf (zamzar.com is an example of a similar service.) This isn't an original idea: PyOD provides one possible solution. (There's also software that runs happily in command line mode to deal with the docx problem if we want to expand this out to a general conversion service ...)
Users can then queue the files for printing or not as the case may be. We use pdf as that gives an ability for users to check the page count before printing, and more importantly for us to display a list of the files awaiting printing and their size in terms of pages, which given that students pay by the page for printing, is all they really care about ...