You can set up Messaging to show text attachments (for mail you receive) either as a link or as text.
From the Account Options... menu, select Set My Preferences.
On the User Preferences page, locate Text Attachments under Message Display Options header and select Show as links or Show with message text.
Click the Save Changes button at the bottom of the page.
If you choose Show as links and you open a message with a text file attached, the text file name appears as a hyperlink; when you click the file name, the text is opened on a new page.
If you choose Show with message text and you open a message with a text file attached, the contents of the text file appears below the message.