I've been having a discussion about licensing and open source software. Basically - the other guy is saying that licensing is easy, if you're going to build a product you can use an (any) open source project and make money by selling that code.

My issue is that say I create a website or app with a project that uses a GPL license the restrictions aren't so straight forward - correct me if i'm wrong on each of these scenarios:

1 - i create an iPhone app using GPL code and put that app into the appstore - the code must be freely available to people buying that app.

2 - i create a website that my client hosts - they must have access to the code.

3 - i create a website as SaaS that my client "leases" but does not own - though it is hosted on their infrastructure - they must have access to that code

Am i right on each of those assumptions?

Are there any other issues i should be aware of under any other licensing terms for other licenses?