the output of command 
FFmpeg version SVN-r8448, Copyright (c) 2000-2007 Fabrice Bellard, et al.
  configuration: --enable-libmp3lame --enable-gpl
  libavutil version: 49.4.0
  libavcodec version: 51.40.0
  libavformat version: 51.11.0
  built on Mar 19 2007 09:51:16, gcc: 4.0.0 20050519 (Red Hat 4.0.0-8)
Input #0, alaw, from 'original.al':
  Duration: N/A, bitrate: N/A
  Stream #0.0: Audio: pcm_alaw, 44100 Hz, mono, 352 kb/s
Output #0, mp3, to 'test.mp3':
  Stream #0.0: Audio: mp3, 44100 Hz, mono, 128 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Press [q] to stop encoding
size=      17kB time=1.1 bitrate= 128.0kbits/s
video:0kB audio:17kB global headers:0kB muxing overhead 0.000000%