If I buy a new MacBook Pro with Mac OS X Lion preinstalled, can I install it on my old MacBook too?
I logged into Mac App Store on old MB but it doesn't give download option. Seems reasonable enoug to be honest but was hoping I could get it free!
No. When it's preinstalled you use the Internet Recovery method to reinstall. If you have another computer with Snow Leopard on it you need to purchase a separate copy of Lion from the App Store. That purchase can be installed on any computer that you own provided the computers that had Lion preinstalled do not require a machine-dependent version of Lion.