The file that you attached was a .pps file. This is a standard powerpoint presentation slideshow file that someone sent to you. If the file doesn’t open when double clicking right off then we need to think about a few things.

1. I like to drag all mail attachments to the desktop then open them from there.
2. If it doesn’t open then you may not have Microsoft Office’s PowerPoint installed. However, there are options. Instead you can use Keynote if you have Apple’s office suite called iWork. You could also use the Free Office suite called NeoOffice. Slower but works just fine.

You can get info on a file then select to always open that particular file type from now on by selecting the appropriate application with the get into window. You can always right click or control+click on a file to get an “open with” option. That menu will display the applications on your mac that you could use to open the file.

Finally, you could also drag and drop the file onto an application that would work. PPS files are generally only viewable with Powerpoint, Keynote, or other office applications like OpenOffice or NeoOffice. By the way, in Windows, the general rule is NEVER OPEN ATTACHMENTS. Not so much an issue on the mac but a good rule of thumb if you’re not expecting to be sent something.

Hope that helps.