monresa, welcome to linuxquestions.org
the gimp is wonderful and FREE, but it's not quite as polished as Photoshop. i run codeweavers' CrossOver Office application in linux. this app is a kind of windows emulator. anyway, i run photoshop 7 and imageready within it to prevent constant reboots (i have a dual boot winxp RH9 system). i have to say that sometimes it seems like photoshop runs faster in linux under emulation than it does in windows natively. i'm not sure how well pagemaker runs under crossover office though. also, crossover office is unfortunately not freeware. you can get it at www.codeweavers.com
for $55. you can also download a fully functional demo that runs for 14 days. oh, and you can run MS Office 2000 perfectly under crossover office, which does help out sometimes. but, openoffice works well for me.