That's one of the last PowerPC-based Macs, before Apple switched to Intel processors. It can run Tiger or Leopard. Some people like Tiger better, but Leopard is newer with additional features, like Time Machine (a automated backup feature) and Spaces (multiple desktops). If you previously used Macs and own even older Mac OS 9 programs, Tiger has the Classic environment that runs a Mac OS 9 system under Mac OS X, to run (most) older Mac OS 9 (and earlier) apps. Leopard no longer has Classic.
According to the EveryMac.com profile, it originally came with 10.4.2 pre-installed. Therefore, you cannot install any version of Mac OS X that is earlier than 10.4.2. If you want Tiger, the installation disc needs have a version that is later than 10.4.2, then update it to 10.4.11. For Leopard, it can be any initial version, then update it to 10.5.8.
You need to find a "retail" disc. These are the discs sold separately in a box, for any supported Mac model. This article shows images of the old Mac OS X installation discs, and offers some advice on sourcing.
http://www.macworld.com/article/2101301/advice-from-an-apple-tech-how-to-get-old -mac-os-x-install-discs.html
Do not get a disc that is grey, because that's a disc that came with a specific Mac model, unless you know for sure that it's from your specific PowerBook model (and you want Tiger not Leopard).
NOTE: Apple still sells the Snow Leopard installation disc, but unfortunately, Snow Leopard is Intel-only.