Frank,
In general the migration is very straight forward. After you get your SMP 3 server and development tools setup you will simply export your application from your Agentry 5.x Editor and then import into the SMP 3.0 Agentry Editor, publish to the server (configuring as needed, especially certificates) and then start testing.
While there are differences between the stand alone Agentry server and the SMP 3.0 server, the core Agentry application stucture is still the same so that knowledge will transfer over. On the server side the admin is different and where the files live has of course changed.
Depending on your backend connections there may be some tweaks needed but generally it just moves across once proprely configured under the SMP 3 structures.
One thing which would impact that is if you want to consider looking at taking advantage of the new WPF client that is eventually going to replace the Windows Desktop client (win32). If so then you will have to look at potential screen, style and image changes to configure for the new WPF client. If you are staying with the same win32 client, then you shouldn't need to do a lot of tweaking.
Please keep in mind that SMP 3.0 is currently still in ramp up and only available for those customers accepted into the ramp up program.
--Bill
