IP Allocation and Management?

jmw asks: "I work for a large[r] regional ISP in the midwest. In the past, and through several acquisitions, we've accumulated a substantial amount of IP space - non contiguous blocks from a /24 up to /19 or more, totaling several thousand IPs. With that many IP's, it's a fairly daunting task to manage, allocate and just keep track of what we have. I'm sure some of you are in, or have been in, similar situations... CVS has been used, but not standardized on.-More people would like to see a pretty web page or the like. For those of you in this situation, what have you done?"