No problem.
1. First step is to create a folder somewhere, mine is called web.
2. Open up a picture that you want to save for web.
3. Do whatever you like to the image, and save the fullsize version on your harddrive.
4. Start an action recording
5. Go to image->resize image
6. Here is the only step that changes between horizontal and vertical. For both, make sure resample image is checked, resolution is 72ppi, and scale mode is Bicubic sharper. Constrain porportions, and make the largest side, horizontal or verticle, 660.
7. The click file->save as->save as same name, but in that new folder you made in step 1.
8. Save as jpeg, quality 12, hit ok.
9. Stop action. Make two of these, one for horizontal, one for verticle.
Then your good. Hope this helps. However, you will have to rewrite the action if you ever move the folder.