macport libusb install?

[liam at makingthings.com]

Hi - just tried installing libusb and stumbled on some of the instructions
at http://libusb.darwinports.com.

Firstly, it says "cd /opt/local/bin/portslocation/dports/libusb" but I'm
not sure what that path is actually supposed to be.  Any tips?  I tried
installing with out taking that step, and the installer finished with no
complaints, but afterwards I'm not able to get any info on where it's
installed (or if it actually is).  Both 'man' and 'which' libusb fail to
return any results and 'locate' just returns

/opt/local/var/macports/sources/rsync.macports.org/release/ports/devel/libusb
/opt/local/var/macports/sources/rsync.macports.org/release/ports/devel/libusb/Portfile
/opt/local/var/macports/sources/rsync.macports.org/release/ports/devel/libusb/files
/opt/local/var/macports/sources/rsync.macports.org/release/ports/devel/libusb/files/patch-darwin.c.diff

Have I missed a step in installing this?  Thanks for any help!

Liam