I'm new around here, first post. But I managed to get the Nagios server up and going on Fedora Core 3 and some clients being monitoring in HP-UX and FC2 with NRPE 1.8. I took the easy way out with rpms and depots but it works and I'm very happy with it so far. I chronicled my setup here.
Just FYI for anyone who might be interested in a quick way to get up and going ASAP. If anyone has any questions afterward I'd be happy to answer them here or on the website. My small contribution to the quality piece of OSS Nagios seems to be.