Iphone call forwarding

I have the blackberry curve and I have been wanting the Iphone for a couple years now. I cannot make the switch because of two key features that I cannot confirm or deny with the Iphone. So my search brings me here. I know several people with IPhone that cannot answer these questions.

First Reason; Call forwarding - I am on my second Blackberry and I must say the forwarding option BlackBerry offers is great! Here is how it goes. there are 4 forwarding options.
A. Forward all calls: This option forwards all calls to a phone number of your choice
B. Forward calls if phone is busy to a phone number of your choice
C. Forward calls for no reply to a phone number of your choice
D. Forward calls if not reachable to a number of your choice

Now here is why this is great. I travel full time and run a business in which I receive a lot of calls. I can setup my blackberry so that when I see a call come I can take it or forward it to my next cell, or to my girlfriends cell phone, or to a land line, or to VM. I can setup up the phone to forwards in all kinds of situations. But the ability to forward the call to my girlfriend where ever she is is just out of this world good! My customers think we are in the office!

Second reason; Push Email, I cannot confirm or deny this is how it works! Everyone I know with an IPhone say's "I think I get my email right away" I cannot find anywhere on Apples website that directly answers this question.

Let me know if you have these answers please. I really like the IPhone and I think I would like the switch.

Thanks,