Like Google Latitude (and other apps), Footprints tracks your location and shares it with others so you can find your friends or track your kids. What Footprints does better is provide easy sharing, less drain on your battery, and the ability to report your location to multiple sources.
While Footprints can eat up as much of your battery as Google Latitude (and others), it allows you to set the interval for when your location is reported so it reports less and therefore uses less of your battery. Sharing your location is also very simple, as you can sync up with Facebook or just select someone from your address book who's also using Footprints. The main downside is that they have to already be in your address book, as there doesn't seem to be an option to just add a contact, but chances are you're not going to want to share your location with someone you don't know so it's probably not a big deal. While Footprints is free to download, an in-app purchase is required to continue using it after the first three months. It's only a few dollars a year, so it's not that bad, but it is more expensive than other apps.
Personally, I'm not a big fan of location tracking apps and generally don't like to use them, but some people do and I do feel there are legitimate uses for them. If you're trying to meet up with people or want someone to know your location for safety (or other) purposes, Footprints is a good choice because it doesn't require much effort and you can share with just about anybody. It has a few drawbacks, but if you're sharing with other iOS users and want a low-battery, private option, it's a pretty good alternative to Google Latitude.
Footprints [iTunes App Store]