Yep, Tim's right.
Free Realplayer will record most online content. It's all you need and plays BBC (but can't rip it) You can then convert to other media types if you want to. Be warned that YouTube is pretty poor for quality. If you go for the full Realplayer it can burn DVDs of your files that will play through any DVD or PC.
If you download any conversion apps use Majorgeeks. They're 100% safe.