Nooo, Zbrush allows you to make models by sculpting like clay on the computer. Maya will have a tool similar to this, but Zbrush is specially designed for it. It ALSO has great texturing tools.
As far as learning, I've always found that the best way to learn something is to do it. (CLICHE!! :D) As in, think up some small specific thing you want to do then Google how to do it. I know that sounds silly, but the biggest hurdle to learning any new program is getting the nerve to dive in and break it a few times. Once you're used to the interface it'll suddenly seem really intuitive and simplistic.
Nogfish
I use 3DStudio MAX, Solidworks and a little Cinema4D
Zbrush is more for painting details into your model in an intuitive-hi poly-photoshop-esque way, it allows you to precisely chip bits away or make scratches.
I'm not really doing it justice by explaining it, but zbrush only enhances Maya or 3DsMAX, I wouldn't use it by itself though I guess you could...
fabulous999
That's what I figured about Zbrush, judging from what I've seen on various CG related sites. I played with 3DS Max 4 a long time ago but never got into it because I just guess I'm a useless lazy bastard sometimes. I'm going the Maya route now since my school uses it and to me it's all apples to apples at this point. Very complex apples with lots of buttons.