While I've never been a fan of online conversion of anything, I do use a lot of PDF's
The best tool I've found for this is OpenOffice. It's an office suite along the lines of MS-Office, and hopefully will one day replace it entirely. With OpenOffice you can simply save your document as a PDF.
Unfortunately this means that you can not edit the PDF itself after it's creation, like you could with Adobe. However you can save your document as a doc file, change it when needed and then simply resave the pdf.
You can find OpenOffice at
OpenOffice.org. This suite is open source and entirely free.