There are a couple of ways. At first boot you are given the option to migrate from an older Mac to newer, or Copy/move Programs, Files and Settings from a Drive or computer, Mac or PC, to the new system.
Then there is Migration Assistant to do this after you have done the original setup on the new system.
I prefer to do it at first boot of the new system as when you use MA it will only work if the user accounts on both Mac's are different and then it creates a second user on the new system that is the older systems user account. Then you have to copy all the files and such over to the new user account on the new system, PITA.
you can get around using MA by Wiping the drive on the new system and reinstalling the OS then at first boot on that reinstall you would get the option to miograte from the older system.
NOTE that some of your older program may not work on the new system. There is No support for older PPC Apps in Lion or Mt Lion