Just for the access and executing commands you do not need php on the windows box, because running commands on the linux box you can simply do with an ssh client.
This command will list files older than 30 days in the specified dir... nearly the same way you could run a script.
ssh 126.96.36.199 find /export/home/*.dmp -ctime +30
But sometimes you need to source your userprofile first, before executing any script:
ssh 188.8.131.52 ". /usr/local/etc/profile; /export/home/local/service stop; sleep 20; /export/home/local/service start\"
So this example shows how to run more than one command in a sequence.
If you now wish to run systemcommands out of your php script, you can e.g. do that with `` (backtiks), exec(), system(), etc... for more see the crosslinks to that commands on www.php.net
EDIT: And that thread (http://www.howtoforge.com/forums/showthread.php?t=7853
) gives you an example how you can directly do an ssh connection with php...