Hello,
how-to videos are my typical jobs. Recently I did a full coverage of how-to's for a large bank in Poland. That included screen-capturing according to the script, hiring a professional voiceover actor, recording session, sound mastering, A/V editing and supplying the video in a required format.
For this task I can provide you with a very good british english native speaking voiceover actor (voice sample on demand) if you want, but my offer has to be 100$ higher.
If this task concerns editing video // video and audio provided, my bid is as stated.
I use Adobe Premiere Pro and Ableton Live 8 as an editing software.
Best regards.