$ffmpeg -f x11grab -r 25 -s 384x240 -i :0.0 -f alsa -i hw:0,0 -acodec libfaac -vcodec libx264 -b:a 64K -b:v 128K -ac 2 -ar 22050 -f rtp rtp://192.168.1.102:8090/stream.ffm
ffmpeg version N-37568-g8162c6f Copyright (c) 2000-2012 the FFmpeg developers
  built on Feb  5 2012 05:59:51 with gcc 4.4.6
  configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-O2 -pipe' --extra-cflags='-O2 -pipe' --extra-cxxflags='-O2 -pipe' --disable-static --enable-gpl --enable-version3 --enable-postproc --enable-avfilter --disable-stripping --disable-debug --disable-doc --disable-vdpau --enable-gnutls --enable-libmp3lame --enable-libvo-aacenc --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-libfaac --enable-nonfree --enable-libcdio --disable-indev=v4l --disable-indev=v4l2 --disable-indev=oss --disable-indev=jack --enable-x11grab --disable-outdev=oss --enable-libfreetype --disable-amd3dnow --disable-amd3dnowext --disable-altivec --disable-avx --disable-mmx2 --disable-ssse3 --disable-vis --disable-neon --disable-iwmmxt --enable-hardcoded-tables
  libavutil      51. 37.100 / 51. 37.100
  libavcodec     54.  0.102 / 54.  0.102
  libavformat    54.  0.100 / 54.  0.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 61.100 /  2. 61.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  6.100 /  0.  6.100
  libpostproc    52.  0.100 / 52.  0.100
[x11grab @ 0x120b530] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 384 height: 240
[x11grab @ 0x120b530] shared memory extension found
[x11grab @ 0x120b530] Estimating duration from bitrate, this may be inaccurate
Input #0, x11grab, from ':0.0':
  Duration: N/A, start: 1328443772.907946, bitrate: 73728 kb/s
    Stream #0:0: Video: rawvideo, bgr0, 384x240, 73728 kb/s, 25 tbr, 1000k tbn, 25 tbc
[alsa @ 0x1205c50] Estimating duration from bitrate, this may be inaccurate
Input #1, alsa, from 'hw:0,0':
  Duration: N/A, start: 1328443772.911403, bitrate: N/A
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
Incompatible pixel format 'bgr0' for codec 'libx264', auto-selecting format 'yuv420p'
[buffer @ 0x1205bd0] w:384 h:240 pixfmt:bgr0 tb:1/1000000 sar:0/1 sws_param:
[buffersink @ 0x12004f0] auto-inserting filter 'auto-inserted scale 0' between the filter 'src' and the filter 'out'
[scale @ 0x1201fc0] w:384 h:240 fmt:bgr0 -> w:384 h:240 fmt:yuv420p flags:0x4
[libx264 @ 0x11ffdd0] using cpu capabilities: MMX2 SSE2Fast FastShuffle SSEMisalign LZCNT
[libx264 @ 0x11ffdd0] profile High, level 1.3
Output #0, rtp, to 'rtp://192.168.1.102:8090/stream.ffm':
  Metadata:
    encoder         : Lavf54.0.100
    Stream #0:0: Video: h264, yuv420p, 384x240, q=-1--1, 128 kb/s, 90k tbn, 25 tbc
    Stream #0:1: Audio: aac, 22050 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> libx264)
  Stream #1:0 -> #0:1 (pcm_s16le -> libfaac)
Could not write header for output file #0 (incorrect codec parameters ?)