From Allok Soft:
Allok MP3 to AMR Converter software is a powerful AMR Converter that lets you convert your audio files to and from the AMR format used by your cell phone. You can convert from WAV, MP3, OGG, WMA, AC3, AMR, 3GP, MP2, RM, RMVB, RAM, VCD, VOB, AVI, MPEG, WMV, ASF, etc. to AMR format quickly and easily. You can also convert AMR to MP3, WMA, WAV, OGG, AAC, M4A, AC3, MP2, AMR with the same ease. The conversion is performed in batch mode, which means that you can easily convert an entire list of audio files to and from AMR with very little effort. Sample AMR conversions include WAV to AMR, AMR to WAV, MP3 to AMR, AMR to MP3, WMA to AMR, OGG to AMR. In addition, you also can convert video formats including AVI, MPEG, WMV, ASF, RM, RMVB to popular audio files. The AMR converter is very fast and easy to use. Advanced AMR encoder and decoder inside. Version 3.0.2 supports Vista.