We need two files. The first one is uploadForm.cfm and it looks like what you see below. I'll let the comments in the code explain how it works.
The second file is handleUpload.cfm. It simply handles the upload on the server side and looks like this:
<cffile action="upload" destination="#expandPath('uploadedFiles/')#" accept="image/jpeg" nameconflict="overwrite" filefield="theFile" />
That's all there is to it. Of course there is more you can do with it as well. You can monitor the progress of the file uploads and return a progress bar, you can FTP, CFMAIL or manipulate the uploaded files and return results, or an endless number of possibilities.
There are a lot of ways to skin a cat - if you have a better way let me know and I'll hold the tail!
And a working demo is located here