Create a Snow Leopard Boot Disk

I was having some issues with disk utility disk repairs and did not have my SL install disks with me. I went to the Genius Bar and they booted my MacBook from a LaCie external hard drive that had disk utility on it. They repaired my disk errors without having SL install CD's.

I want to create a boot disk with disk utilities so I can take it with me (on the same Iomega hard drive I have backup files on) when I travel. I don't want to carry my original SL install CD's with me. How do I create a boot disc on my external hard drive that has existing files on it? It would be nice to have one external hard drive that I could use as a bootable disk (with disk repair utilities) and also use it to back-up and store files.

Thanks and Happy Holidays.

OK. Played around with disk utility and found a way to do this.

1) I partitioned my external HDD by using the GUID partition table;
2) Inserted my Snow Leopard install disk;
3) Created a new image (dmg) of the SL install disc on my desktop;
4) Scanned the new dmg file with disk utility (under images>scan image for restore);
5) Selected the new HDD partition and selected "Restore" tab in disk utility;
6) Selected the SL dmg file as source and dragged the hdd icon in the left menu to the destination field;
7) Hit apply.

Now I have the SL install disk on hdd if I need to reinstall or fix disk errors and/or permissions.