If it's a Windows VM, you can get the IP with the following command from the host:
prlctl exec "VM Name" ipconfig | grep "IPv4" | grep -o '\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}'
For a *nix VM:
prlctl exec "VM Name" ifconfig eth1 | grep "inet " | grep -o 'addr:\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}' | grep -o '\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}\.\d\{1,3\}'