Looks like someone sent you an email in Rich Text Format (RTF). There are special codes (just like HTML, except the user never sees them) that control how characters are displayed. If they are viewed in a non-compatible program (like Mail currently is) they show up as weird text combos.
Formatting your emails as rtf is an option in Outlook (last time I looked) and very common for internal mail inside larger enterprises mostly those running Microsoft Exchange servers. Microsoft is the mother ship of rtf.
iOS 5 is supposed to add rtf text compatibility to Mail.