For some reason, libusbJava did not want to compile on my linux system. It consistently issued warnings that some "libusbpp.so" (which I still have yet to figure out what the heck it is) was missing. I did some googling, and eventually managed to compile it by hand using this command:
g++ -shared -Wl,-soname,libusbJava.so -I/usr/lib -I/usr/lib/jvm/java-6-sun-126.96.36.199/include -I/usr/lib/jvm/java-6-sun-188.8.131.52/include/linux -shared LibusbJava.cpp -olibusbJava.so.0.2.4 /usr/lib/libusb.a
Note that the /usr/lib/jvm/java-6-sun-184.108.40.206 paths are specific to whatever version of java you're using.
Anyway, with that taking upwards of an hour to do, I figured I'd post a pre-built binary for anyone that's looking for one. This was built on Ubuntu 9.04 against libusb-0.1-4 (Synaptic reports its version number to be 2:0.1.12-13; I'm not knowledgable enough to know the difference between the two), so I won't make any guarantees as to whether it will work properly on your system. You can download the binary here.