The font used in received messages is controlled by the sender. You still have options :My in-laws have AOL e-mail and would like to be able to read it, but because of the small font have difficulty doing so. I have found how to increase the font of their OUTGOING messages, but that doesn't help with the incoming.
1) Use the Windows Magnifier accessory.
2) Copy-and-paste the text into Notepad or a word processor where you can change the font as desired.