If you really want to know ill list the information for you from past experience:
US Army Sniper school is around 5 weeks long, bout the same for the Marines:
Prerequisites
Must be 11B, 11M, 19D, or CMF 18.
PFC-SFC (Grade waiverable).
Active duty, or Reserve, or National Guard, must have a good performance record with no history of alcohol, or drug abuse, must be a volunteer and be recommended by his commander.
Must be in excellent physical condition (70 percent or better in each event of the APFT).
Must have a corrected vision of 20/20.
Must not have a record of disciplinary action.
Must be knowledgeable of skill level 2 tasks.
Must have a GT score of 100.
Must have qualified expert with the M16A2/M4 Carbine rifle within six months of course attendance.
Normal color vision must be annotated on SF 88, tested within six months of course attendance.
Must have a minimum of one (1) year retainability.
Must pass psychological evaluation (MMPI/CPI) conducted under the direction of a qualified psychologist.