redirect to a new URL

[emath]

hey, im moving my site domain from math-pl.co.il to emath.co.il .

ive copied all the forums to be under emath.co.il, though, i need that my users who usually entering the math-pl url to be redirected to the emath.co.il url to the same thread.

for e.g if the thread is :
http://www.math-pl.co.il/forums/showthread.php?t=5587

so it will be redirect immediately to http://www.emath.co.il/forums/showthread.php?t=5587

i know its a simple php code and should be in the header but ive no idea how to do it.

any help ?