We have been doing screencasts for a while now and use Screencast-o-matic. It has completely hit the spot in terms of being easy to learn, quick to get going & simple to share once done. We even added subtitles. I can't recommend it enough therefore if you just need to do it with no frills.
Personally, I find it easiest to write out almost a script to have in front of me. I also accept it's not going to be perfect. I genuinely believe anything over 2 minutes is too long - no time can be wasted on intros, you have to jump right in and be as quick as you can. They can always be re-watched...
The issues we hit were
- Media complaining about the quality and other aspects, compared with more professional tools. Basically, they expected us to be using Camtastia or similar. However, we don't HAVE copies of a posher tool nor do we have the time to learn it. The quality is definitely sufficient to tell someone how to do something and that is all we need. (Media were only involved at all as they said we have to host the videos on "estream").
- Backing them up. We tend to link back to the website but really we ought to download them just in case it went pear-shaped. We are supposed to put them on our institutional "estream" so this would achieve this.
- Finding a place to do them. We have an open plan office so to do one you need to book a room, use a laptop, find headphones, get it all set up to work etc. It's a huge faff! This is particularly annoying as I'd love to be able to do a quick screencast sometimes to answer a question - so many of our queries are about accessing online resources and it would be ideal for that.
- We already have a whole swathe to update this summer as interfaces change. This isn't a huge problem - I was able to reuse the "script" from before so it didn't take as long as the first time to do.
Hate listening to podcasts & don't make them. That sounds terribly churlish but I felt the screencasts were enough for one year! Also I prefer a visual medium - I'm not sure I have anything to pontificate on that would fit an audio format?