The acquisition of another servent’s address

I have some questions related to the Gnutella design...

1) Does it depend on any central server (as Napster do or even as kazaa does for the users registration) ?

2) I read the Gnutella protocol but i found this:

"A Gnutella servent connects itself to the network by establishing a connection with another servent currently on the network. The acquisition of another servent’s address is not part of the
protocol definition and will not be described here (Host cache services are currently the predominant way of automating the acquisition of Gnutella servent addresses)."

does anybody know how the first host is found? what technique is used? what is the host caching service?

Thanx in advance