HOWTO: convert amr ringtones or voice recording to mp3/ogg/wav

First you should decode the file to the raw format:
$ amrnb-decoder Sound1.amr Sound2.raw
which should produce something like this:
================================================== =================
TS 26.104
REL-5 V5.4.0 2004-03
REL-6 V6.1.0 2004-03
3GPP AMR Floating-point Speech Decoder
================================================== =================

Secondly, you can convert the resulting .raw file to other preferred format in Audacity.
In Audacity, using 'File->Import->Raw Data' to open the raw file by selecting 8000 as the sample rate.