Amir,
We do not provide intrinsic support for third party plugins but we will try to assist you in this case. I am afraid we do not have any tutorials for XAMMP in MyEclipse.
If you can find a tutorial for XAMMP and Eclipse, you can try following the same steps for configuring XAMMP in MyEclipse.
Couple of links for Eclipse +XAMMP :
http://www.cs.trincoll.edu/hfoss/wiki/How_to_Setup_Eclipse_with_XAMPP
jonathansblog.co.uk/setting-up-eclipse-to-work-with-xampp-and-xdebug-to-debug-php-code
For more information on XAMMP configuration on Eclipse, I suggest you check on Eclipse related forums.
Hope it helps.