Mostly for my future reference. ‑threads 8 should be changed to the number of CPU cores (my i7 has 4 with HT, thus I set it to 8).
ffmpeg ‑i input.avi ‑acodec libfaac ‑ab 48k ‑vcodec libx264 ‑vpre fast ‑vb 500k ‑threads 8 ‑f flv output.flv