building an a/b box

[Narcosynthesis]

right, i found this schematic



thing is i would prefer to build it with led indicators to show which output is selected, how would i add these into the circuit?

and this would need a battery to be added, but i hopefully intend getting a power supply sometime soon so would like it if i could use either a supply to power the led's or a battery, does anyone know how i could add this into the circuit

and last of all, what parts would i need to get, there is a maplins where i live so i would prefer to be able to buy from there, i knw they make die cast aluminum enclosures so i would hopefully use one of them, and i know i need three jacks (opne style, mono or stereo?)
im not sure what switch i would need or what jack i need for a power supply, could anyone direct me to what i need?

much thanks

David