What sort of attachments?
Actually, never mind, let me guess. It will be one or more of the following types of attachments:
1. PPS (powerpoint) slideshows
2. WMV or AVI videos
3. Excel spreadsheets
Solution to (1) is to get a copy of Keynote ($20 from the Mac App Store) or Microsoft Office ($100+) or LibreOffice (free).
Solution to (2) is to download and install the free
Flip4Mac WMV Player and
Perian add-ons.
Solution to (3) is to buy Numbers ($20, Mac App Store) or Excel (part of MS office) or LibreOffice (free)
(for "LibreOffice" you can also substitute NeoOffice and OpenOffice, they are essentially the same thing -- a free open-source knockoff of MS Office)