I want to port 127:0.0.1:80 to the other machine via SSH, how can I do that? I tried adding -R 8000:localhost:80, but it doesn't work. By the way, PHP is also installed on localhost, maybe that's why?
Only root can bind ports numbered under 1024.
The cleanest way is just to use local port 8000:
ssh -R 8000:localhost:8000 otherhost
sudo ssh -R 8000:localhost:80 me@otherhost
(It's really better not to run this as root for the sake of security - just use another port.)
If you must use root, and you're using ssh private-key authentication, you may need to tell it which identity file to use. For example
sudo ssh -i ~/.ssh/id_dsa -R 8000:localhost:80 me@otherhost