Can apps purchased from one Apple ID be shared between multiple iTunes libraries? We have a number of iDevices in the family, and each user has their own Apple ID. Also, each person has their own computer to sync apps and other content.

If I purchase an app for my iPod, Can I share it with my wife and son, each of whom have their own IDs?  

If so, how do I share purchased apps, if each person has their own computer or iTunes library?
Unfortunately the only way to share apps is to use the same Apple ID for purchases on every device. 

You can use different IDs for iCloud, but you need to sign into the App Store with the same ID.

If you're signed in to the App Store with the correct ID you can download previously purchased apps for free, each person haven their own computer and iTunes library doesn't matter.