A frequently asked question on many Blogger user groups is "How do I upload files to my blog?". Files refer to types of files such as .doc, .xls, .pdf etc. The simple answer is, you cannot upload any files to Blogger, other than images. But, don't worry, there is a simple alternative.
All you have to do is to upload your file to an online hosting service and link to that file from your Blogger blog. There are many free hosting services available today. Just google for "free file hosting" and you would a get a zillion of hits.
One such service is Google Pages, which allows you to create up to three accounts, each offering 100 MB of free storage. For example, the free resources provided by The Blogger Guide's three column conversion tutorials, wider post column tutorials, and the pdf file showing a mapping of CSS styles to Blogger templates are all hosted on such a Google Pages account.
Update: (2009 Sep 23)
Google Pages does NOT offer new accounts now. Fileave.com is another free file host.