American Friends Service Committee's "Youth and Militarism" website has an excellent article on Vietnam war resisters I've excerpted here:http://www.afsc.org/youthmil/html/news/may00/resist_prt.htm
War Resisters and the Courts
Draft Law Violators – During the entire Vietnam War, 209,517 young men were formally accused of violating draft laws. Government officials estimate that another 360,000 were never formally accused. Of the former group, 25,000 indictments were handed down; 8,750 were convicted; and just under 4,000 served jail time.
Military Resisters – It is difficult to say how many military service members were prosecuted for offenses growing out of opposition to the Southeast Asia War. Most estimates consider the rates at which service members went AWOL (absent without leave) or deserted – commonly referred to as "absence offenses." AWOL and desertion rates hit an all-time high during the Vietnam War, 1971 and 1972 being the peak years. The Pentagon documents 1,500,000 instances of AWOL and desertion during the war. Official estimates of the actual number of service members who went AWOL or deserted run between 500,000 (Pentagon) and 550,000 (officials in the Ford Administration). It is important to remember that not all service members who received bad discharges for offenses related to the war were absentees. Adding other types of anti-war activities for which service members were prosecuted significantly increases these figures. Many went to jail and/or received bad discharges.*
Resisters in Exile
Estimates of the number of draft and military resisters who went into exile during the Vietnam Era vary widely. The best estimate is about 100,000, at least 90% of whom went to Canada. How many are still living abroad is unknown. The New York Times estimates that 25,000 draft resisters still live in Canada, an estimate which seems high by most accounts. (This figure does not include active duty service members who went into exile.) There are no reliable estimates: it is most likely still in the thousands.