Ethernet-WiFi bridge
We have tested using the D-LINK DWL-G700AP, works like a charm. They aren't too expensive either, available in Sweden for something like 50 EUR. Installation is easy, just put it in "repeater" mode, enter your wireless network encryption settings and it's running. No changes at all are required in Bubba's setup.
There used to be smaller devices available, made for laptops without built in WiFi, but they don't seem to be manufactured anymore.
Summary:
+ Fast
+ Easy to install
- Physically large
USB dongle
This is the neatest since the devices are quite small, but the downside is that it occupies your USB host connector. However, if you need to run something else simultaneously, maybe a printer, it's just to place a standard USB hub in between.
Make sure that Linux drivers are available for the USB dongle you select before purchasing. Note that this requires driver installation on Bubba, and Linux knowledge.
Summary:
+ Small
- May be tricky to install
- Occupies the USB connector
- Slow (max ~10 Mbit/s)
Edit: According to this the transfer speed will be something like 5 Mbit/s, including routing. I guess 10 Mbit/s was a bit optimistic.