The bitkeeper repository is available here.
You can clone a copy of my trees from there, and update from them if you wish (I usually merge new kernels pretty quickly from when they are released.)
To clone the 2.2.x tree run:
bk clone bk://linuxusb.bkbits.net/usb-2.2 usb-2.2
To clone the 2.4.x tree run:
bk clone bk://linuxusb.bkbits.net/usb-2.4 usb-2.4
To clone the 2.5.x tree run:
bk clone bk://linuxusb.bkbits.net/usb-2.5 usb-2.5