Another program worth checking out is
Ulead DVD workshop
You can get a 30-day trial, this is an excellent entry-level program and very user friendly. You can get the studio-author look using drag & drop features within minutes.
All the conversions are done automatically for you when burining the final DVD, before that you have a nice preview mode that will show you how the final DVD might look like.
Nero Ultra is
not a free software, it is also not aimed for DVD authoring, not that its bad (I'm using Nero 6.6 myself) but if you are more creative person you should check out Ulead.
NR.