IPM is a system of dealing with pests that uses information about them to control them in a variety of ways- not just pesticides, but physical barriers, changes in farming/gardening practices, biological control, etc. All of these are supposed to be integrated so they reinforce each other.

Because IPM is based on knowledge about the pests, IPM references tend to have a great deal of useful and interesting information about the species covered. This site is no exception- The "Pest Notes", especially, are very informative and cover a wide variety of bugs (among other types of pests).

Even if you don't consider your bugs to be pests or want to control them, you can still find lots of good information here, produced by a reputable academic institution.