Versant, an interesting non-profit, is tackling nurse retention from an unique angle: providing an "RN Residency" program at your hospital. A quote from their website:

"Unable to handle the intense pressure and resultant stress, new nurses leave their first employment situations at alarmingly high rates in the first 12 –24 months of service; new graduate RN turnover currently runs between 35-60% within the first 12 months of employment"

So far 700 nurses from 13 hospitals have graduated from the program.