Free? Is your first instinct to say "Nothing is free"? Hmmm. Adobe Reader is certainly free, but you can't use it to created PDFs. All versions of Acrobat 9 facilitate PDF creation in a variety of methods–but they are definitely NOT free!
The answer is not on your computer, but rather in the clouds. Clouds? Specifically, Adobe is now providing online services via Acrobat.com, a suite of free Web-based utilities. To use them, you need only to sign up for the service–provide a user name and a password and you're in! You get two gigabytes of storage, file sharing, online conferencing (Adobe ConnectNow), a word processor (called Buzzword), and the ability to create PDFs.
When you log on to Acrobat.com, you will notice that the service is still referred to as 'beta,' but I believe the fact that there is an 'Upload to Acrobat.com' button in Acrobat 9 indicates that Acrobat.com is not going anywhere.
There are a few limits to the free service. First, your ConnectNow conferences are limited to three participants. Second, as I mentioned earlier, your file storage has a two gigabyte limit. You can only create five PDF files online, and if you want bigger conferences, you'll have to buy Acrobat Connect Pro. (If you need to make lots of PDF files, you should buy Acrobat 9.)
You can use Acrobat.com to create PDFs from any of the following types of files: Microsoft Word (DOC), Microsoft PowerPoint (PPT), Microsoft Excel (XLS), text (TXT), Adobe PostScript (PS), image (bitmap, JPEG, GIF, TIFF, PNG), Corel WordPerfect (WPD), and OpenOffice and StarOffice presentation, spreadsheet, graphic, and document files (ODT, ODP, ODS, ODG, ODF, SXW, SXI, SXC, SXD, STW).
If you decide Acrobat.com is a service you would likely use often, you may want to download the desktop version of Acrobat.com (a smooth Adobe AIR application that has all the functionality you'd expect without having to launch a browser). This app can be minimized to your Windows tray, or shown as a cool little desktop widget.
If you find yourself with a borrowed laptop, or sitting at someone else's computer, and you need to make a PDF file, Acrobat.com can come to the rescue!