There are some useful and free tools on the Web for creating, modifying and exchanging documents, and here are a few.
I have two sites For PDFs (Portable Document Format). The first site is KoolWire.com, which automatically converts Word (.doc), Powerpoint (.ppt), Excel (.xls), Jpeg, GIF, Rich Text Format (.rtf),and Text (.txt) files to PDFs. You attach your files, email them to the site, and they are immediately returned to your email as PDFs. Couldn't be easier.
The second PDF site is PdfPad.com.This site contains pre-made documents, like calendars, graph paper, sheet music, and even Sudoku.
If you want to create diagrams, try Gliffy.com. Options include IT-related tools for flow charts and relational databases, and basic floor plan design tools. Diagrams can be exported as JPEG, SVC and PNG files; or, you can embed the diagram in Webpages with linked code (the same way those YouTube videos are embedded on various Websites).
Let's say you have a big batch of photos that you want to email to relatives, or a you have a video for school project you need to get to a classmate, but your email system can't handle such big files. You can put the files (up to 100MB for free) on YouSendIt.com which will email a ftp (file transfer protocol) link to the recipient, who can download the file from the site. It's easy and it's free.
Some of these sites may offer higher levels of services that they charge for, but the free services are useful for a lot of common document problems.