Matthew-Hsu has released PiPass, software which turns your Raspberry Pi into a Homepass relay Station for the 3DS, if you do not have a Raspberry Pi, you can use Linux, here is a quote from the source:
PiPass turns your Raspberry Pi into a Nintendo 3DS Homepass Relay Station. The PiPass Dashboard can be accessed through a computer or mobile device. It can manage features without the need of opening up any files manually. However, some fine-tuning may require getting your hands 'dirty'. Though the process is relatively fast and easy.
Here is a video of it in action: