I put Debrox drops (or the generic equivalent – I prefer CVS brand because it has a better dropper than Walgreen's) in Trevor's ears (LI, 27 months old) about once a week. These days it's usually at night while he's sleeping, although when he was younger he let me do it just about any time. The following evening, after bathtime, I scoop out the wax using a tool his pediatrician gave me. I've seen them at drugstores - to see an example, search for "Ear Wiz" at this site: http://earplugstore.stores.yahoo.net/
It works great, just have to be careful not to dig too deeply. Of all the care we do for his LI, this is the one routine that Trevor actually seems to like.