tv.begin(PAL) will work fine , but if i may share my experience's with you..
i had trouble geting TVOUT to work in some of my pal tv's ,i would get ghosted picture's and could not read the screen my fix was to get the latest beta http://code.google.com/p/arduino-tvout/downloads/detail?name=TVoutBeta1.zip
and i added a 75OHM resistor between VID and Ground then opened the PALDemo and that worked lovely...
i then read the PALDemo and started my own script testing out how to put in bitmap's with Image2Code-1.1
it isnt two hard just check your pins with a multimeter first two make sure your getting the right level's (before i added the 75oHm on VID/gnd i was getting between 2 and 4 volts after its was more like 0-1V witch is the right voltage
hope that help's some