Here I want to recommend a totally free software called Freez iPod Video Converter. It can convert FLV to MP4 video format. The output MP4 files can be divided into 2 types. One is MP4 encoded by MPEG-4 and the other one is MP4 encoded by H.264. Of course aspect from FLV, you can import AVI, MPEG, WMV, ASF, MOV, RM, RMVB, DivX, Flv, SWF, VOB, 3GP to MP4 compatible with your favorite iPod.