I have a webpage where people can submit updates and corrections to the directories I publish.

I'm using a set of forms to collect this information, which is then parsed into a spreadsheet/database later on. Often times people have files they would like to submit (usually PDF or DOC format).

I would like to make it convenient for people to upload files at the same time they are submitting their form data. What would I need to do to accomplish this? Aside from the potential risk of viruses within the uploaded files, what other security concerns/risks would there be?

You'd need some kind of server-side scripting - PHP, .Net, etc.

One of the risks is submitting the file that is too large, need to set max limits.