I have OS X 10.7.5. I have used the Epson download to install the 3880 on my Macbook Air. But when I go to install the printer into Printers and Faxes, it can't find the drivers. Do I have to upgrade to mountain lion? Why can't I just install the printer as I always have?
If you have not done so, try rebooting you computer and repair disk permissions using Disk Utility in the Utilities folder. Afterwards, try adding the printer again.
Adding a printer in OS 10.6 is "Print & Fax" in System Preferences. In OS 10.7.x it's "Print & Scan."
For 10.6.x see Apple's KB article Mac 101: Printing (Mac OS v10.6)
For 10.7.x see Apple's KB article Mac Basics: Printing in OS Mountain Lion & Lion
If the printer is connected to a network, see Chapter 1 of the User Guide for setup instructions.
I do not recall any issues with adding the Epson 3880 to a MBPro with 10.6.x nor a different MBPro with 10.7.x.