Hello everyone! Thanks so much for all your input. Yes, AtomSoft, your explanation was definitely easier to understand for a novice like me.
Just to clarify, I'm happy to use either 9v or AA's and seeing as my son is extremely, enthusiastically wanting lights, I imagine they'll get a fair bit of use. Hence me wanting a circuit that turns off automatically. So what every you guys think would work best, I'm up for. I'd really appreciate someone drawing me a circuit which contains either the CMOS or the CMOS Multivibrator, as the idea of my batteries lasting only a week worries me.
Regards,
John (and Roadrunner Junior)