Connect with your site's url, and your hosting account's username and password. If you can't connect then the ftp server may be offline; check in your account CP to check the status (http://x10hosting.com/account).
Ok, i checked, and it said FTP was online, but when i go to connect it says:
can't establish connection --> ambiencex10hosting.com:21 @ Sat Nov 17 20:57:19 2007 (11004-100)
The requested name is valid, but no data of the requested type was found.
or it says:
USER trip
331 User trip OK. Password required
PASS **********
530 Login authentication failed
USER tripwire62
331 User tripwire62 OK. Password required
PASS **********
530 Login authentication failed
Edit:
Ok people, I got it, i connected to the IP address of the server.