I agree with alexm, you should use ssh , otherwise any attempt to hide the password will be utterly useless (for example, the user and anyone else on the network could simply listen to the network traffic generated by your script and read the password that way).

Also, ssh gives you the possibility to execute only a specific script/command on the remote machine, via the "forced command" mechanism. You could generate an ssh keypair on the local machine, transfer the public part to the remote machine and assign it a script to execute. Your local script would then work without a password, but only enable the running of a single command on the remote server (which I think is what you're after).