http://www.adobe.com/support/downloads/main.html

Scroll down to the Download link
Then find your OS and Direct Download it.

This program is large at 329.1mb. It could take quite some time to download.

Another bonus to this is that it has a Mac version.

1. Run the program
  Open the image in Photoshop.

2. Click on Image > Image size
  Make sure Resolution is 72
  Set width and length to be under the 480pixel x 640 pixel limit.

3. Click on Filter > Sharpen > Unsharp Mask
  I find it best to keep the radius and threshold small, in fact, I never change them unless I need to do something   special. Then I run the amount usually between 20 and 60, averaging more in the 30-40 range.

Now for the best part, the reason why Adobe rules the roost!
4. Click on File > Save for Web

- Note the circled areas. Circle #1 should be JPEG. Circle #2 you can scroll. You will see the quality, how nice the image will look when you are finished saving. Also note the circle marked Whoohoo!. That shows the final size of the document. Keep in mind that all programs have an actual size and a file size. The file size is about 2-3kb LARGER than the Actual Size. This show Actual Size. For web upload, they only look at File Size. So make sure this number is 37 kb or smaller and you are good to go.