Crontab to move file between servers?

I've got two UNIX platform servers. On server "A" I have created a crontab to backup my entire web site root directory to a .tar.gz file which it saves into my user home directory on a regular basis. Now I want to figure out a way to move that backup file to server "B".

The two servers have different IP addresses from each other in case that matters.

I had a tip I found along the line which used a 'wget' command to do this from server "B" but I could not get that to work. My server says it did not recognize the command.

I tried to create a cron job on server "A" using something like

0 0 * * 0 mv /usr/home/user/backup.tar.gz 123.123.123.123/backup.tar.gz

<Where '123.123.123.123' is the IP address of server "B">

If I run this from command line I get a return that says there is "no such file or directory". I believe that is referring to server "B" not the origin server "A". I can see that the file does exist on server "A" right where I specified it to be.

I am obviously missing something here or it just is not to be done.
Is there a way to do this??

no chance to do that this way
- be sure the sys are connecting
- use ssh or scp or a kind of ftp in batchmode