If you are already using Gmail, you already have access to Docs (we'll use this pet name for the rest of this post). Log into Gmail, look in the top left corner and click on the 'Documents' link. If you haven't used Docs before you may have to set it up first, but it is really quick.
If you aren't using Gmail already, why the heck not? It is really awesome! Go get your account right now! ;-)
Alright now, so you've found your way to Docs, great! Click on the 'Upload' button at the top left corner.
On the next page, click the 'Select files to upload' link. It opens up a dialogue where you can pick the file you want.
Once you have chosen the file(s) you want to upload, click the 'Start upload' button and wait for the magic to happen.
There we go, it's uploaded to Docs! Now click on the link for your document.
It opens up your document in the Google document viewer (or whatever it is called..). At the top left is a 'Share' link, click on that and then click the 'Get the link to share' option.
Check the 'Allow anyone with the link...' option, copy the link which you can then share with others on your blog, in email etc. Then click 'Save & Close' and you are done! The link will be pretty long, so you might want to use a URL shortening site like TinyURL.com.