I like to download the ROM to my SD card, extract the .nbh file to the root of the card, and flash on the go.... Works like a charm!
When trying to do this with the latest release I found out that pocket RAR will not open the new 7zip format that NRGZ is using for the ROMs going forward. Here is the link to a mobile version of 7zip for those of you who want to flash on the go!
http://freewareppc.com/download/utilities/7zip.shtml