I've heard a rumor that you can enter a bar code number (or something of that sort)off a gameboy advance or DS to get Wii points. I really doubt this is real but, has anyone else heard of this?
No, it's not true. However, you might be confusing it with a Club Nintendo Star Points scheme used here in Europe. If you live in Europe you do get Star Points with a DS and GBA (as well as other Nintendo consoles and games), which can be exchanged for Wii Points (at a rather steep exchange rate of 4SP=1WP) on the Club Nintendo website.