I have a PM-A900 myself, and I've had a lot of trouble with the printer drivers for it. I first tried the official Epson one at
http://www.avasys.jp/english/linux_e/index.html (the English model number for mine is the Stylus Photo RX700, I'm not sure what yours is. Maybe the RX600?). Unfortunately though, I could never get it to compile. The Avasys drivers seem to be coded for an older version of gcc or something and many people seem to have trouble compiling them.
Fortunately for me though, the Gutenprint driver now supports my model. It's not perfect though. It has a margin setting problem that I can't seem to work around. But for the most part it works, and that's all I need for now.
So I'd suggest trying to get the Avasys driver working first. If you're using an rpm-based distro, it should be easy. If you need to compile it, then good luck!. If that's no good, or if you want a Free driver, then you can see if Gutenprint works for you.
If you're willing to go the commercial route, there's also TurboPrint for Linux, which might support your printer (It doesn't work with mine yet).
http://www.turboprint.info/
BTW, as for the scanner driver, I had no problems with the one from Avasys, once I got it working.