Here is a PDF document from Linear Technology, featuring current sense circuits for different applications, including High side, low side, level shifting, high and low voltage, fault sensing, etc: [via]
Sensing and/or controlling current flow is a fundamental requirement in many electronics systems, and the techniques to do so are as diverse as the applications them-selves. This Application Note compiles solutions to current sensing problems and organizes the solutions by general application type. These circuits have been culled from a variety of Linear Technology documents.
Current sense circuit collection – [Link]