For grants you will apply US Federal Grants though the US government, along with Federal Student Loans, If your online school is an accredited college, you can receive money if you qualify.
Home - FAFSA on the Web-Federal Student Aid
When you apply for the FAFSA, you will pick the school year you want to go, if you are going in sept, that is the 2013 school year, if this summer still it is the 2012 school year.
It wlll ask you to enter the school ID number for a school you are looking into, you can enter several schools. If you choose another school they have a method of that school reviewing your information.
You can apply online, no paper application any longer and can get approval back within a few days.
You may have to provide your parent income info, depending on your age and other factors.
There are many good school programs, but you can not be a nurse online.
You can get a criminal justice degree with study in forensic science, but it is more from the investigation and criminal procedure and evidence collection side.
For study about labs and testing you will need a brick and mortal school.
Many of the larger State schools, Kentucky, Missouri all offer online programs as I am sure many more.