Quick update: if you're using Photoshop CS4, you'll want to download the filter here: http://www.adobe.com/support/downloads/detail.jsp?ftpID=4048. If you're using Photoshop CS5, the filter has been deprecated. You want to use the Refine Edge command (Select > Refine Edge) and use the Refine Radius tool (E) to brush over the desired area.
I am using CS5, I upgraded from CS4. I went to the Adobe website you indicated above for getting the extraction tool and it said do not download to CS5. My computer appears to have CS4 and CS5 on it. Can I download to CS4 without affecting my CS5 upgrade or should I wait to see if they are going to add it to CS5. Although I don't use this a lot it seems to be a snap based on your tutorial and I would like to have it. Why do they take these things out?
The Extract tool was bumped from CS4, it's now part of option extras found in the Goodies directory of the install DVD. You can also download it from Adobe. Here's the link for the PC version: http://www.adobe.com/support/downloads/detail.jsp?ftpID=4048