How long is it going to take for the .mobi domain registrations?

I'm not 100% sure of what you're asking, so hopefully one of these will answer your question:

You can register .mobi domains on June 12 if you're a trademark holder or Aug 28 for the rest of us.

Now if you're asking how long it's going to take to register one, I find most domain registrations with Stargate or DirectI to be near instant.

I pre-registered two domains several weeks ago, and I was just wanting to know when they would be available.

I'm guessing then August 28 since that is when public registration begins, but I don't know of any registrars doing pre-orders so I'm not 100% sure.