From the organization’s site:
The 2013 Hugo Awards are being administered by LoneStarCon 3, the 2013 World Science Fiction Convention in San Antonio, Texas. Any person who was or is a member of the 2012, 2013, or 2014 Worldcons as of January 31, 2013, is eligible to nominate for the 2013 Hugo Awards.
Eligible members can cast a nominating ballot through the LoneStarCon 3 Hugo Nominating Website or by paper ballot by mail. LoneStarCon 3 must receive ballots (postmarks/timestamps do not count) by Sunday, March 10, 2013, 11:59 pm Eastern Daylight Time.
The categories include: Best Novel,Best Novella, Best Novelette, Best Short Story, Best Related Work, Best Graphic Story, Best Dramatic Presentation (Long Form), Best Dramatic Presentation (Short Form), Best Editor (Long Form), Best Editor (Short Form), Best Professional Artist, Best Semiprozine, Best Fanzine, Best Fancast, Best Fan Writer and Best Fan Artist.
Check out last year’s winners here.