The Law:

Felons on probation, in prison or on parole cannot vote. Once an individual has completed his or her sentence, the right to vote is automatically restored.

Getting Your Vote Back:

http://www.aclu-wi.org/wisconsin/voting_rights/whocanvote.shtml
http://www.sentencingproject.org/tmp/File/Collateral%20Consequences/Wisconsin.pdf

More Information:

http://www.aclu-wi.org/wisconsin/voting_rights/whocanvote.shtml