flumotion in extras-devel will let you create an http stream from your webcam. The one in extras-devel currently only supports ogg/theora/vorbis streaming but I will be putting one later in the week that does webm/vp8/vorbis and h264/aac/flv.

An example for now (note n900 cpu may be too slow really to do theora encoding):

flumotion-launch pipeline-producer pipeline=v4l2camsrc device=/dev/video1 ! theora-encoder ! ogg-muxer ! http-streamer port=8800 mount-point=/webcam.ogg

Please note that software in extras-devel is installed at your own risk!