Who uses unity?

Hello, I want to begin developing iphone games, and I have never used a big and complete engine like unity before.

My question is, do artists use unity? or just developers?

I ask this because I will start a project soon, but am not at the point where I can start developing anything. Right now my brother(artist) and I(programmer) are finishing up the game designs, and planning how we will develop the project. I need to know if he will need to use the engine to develop art because we can't afford two 3000$ licences.

I was wondering if a developer can do all these things like lighting and what not or do usually artists do those? I am not experienced with large projects... We mostly just made small demos together with small 2d engines.

Good news, you don't have to worry about any of that. You can use your single Pro license on two systems Unity Faq. A programmer or artist can do things like lighting, placing assets, it very easy to do through unity editor.

To make your 3d art you might want to try Blender (free) and start making game assets now.

Unity is selling per seat which means one at a time, but you can have multiple users at one seat. (no lawyer, just googled the definition)