Thanks Scott. Actually I've looked the Epson's Snow Leopard support page. There they recommend, as you do, to download the 6.60 driver for the 3800. Well... I must admit I can't find that driver for the 3800.
I also tried this way, recommended from Epson for the 3880,
Thank you for taking the time to contact Epson. It is my pleasure to respond to your inquiry.
Here are the steps to resolve your issue:
1. Go to System Preference > Print & Fax.
2. Highlight the Epson printer and click - to delete.
3. Go to MAC HD > Library > Printers.
4. Drag the whole Epson Folder to the trash.
5. Go to Epson.com and download the Printer Driver v6.60 from your printer's support site.
6. Install the driver.
7. Once installed restart the computer.
8. Once restarted, make sure the printer is on and connected. Go to System Preference > Print & Fax.
9. Make sure the printer is on the list.
Try printing again.
Not being able to find the 6.60 I've tried to do the same with Printer Driver - Tiger v3.57, Leopard v6.11, with no fortune...