Earlier this week, the USPTO issued a Notice of Proposed Rulemaking to implement the micro entity provision of the Leahy-Smith America Invents Act (AIA). If an applicant qualifies as a micro entity, then the applicant is eligible to pay reduced patent fees once the USPTO exercises its fee setting authority under the AIA (in the months to come). The fee setting provision in the AIA sets the micro entity discount at 75% of the fees set or adjusted for filing, searching, examining, issuing, appealing, and maintaining patent applications and patents. (proposed rule set here)
Generally, in order to qualify as a micro-entity an innovator must have filed a limited number of previous patent applications and have an income of (roughly, based on 2011 median household income estimates) less than$150k.
Unfortunately, Congress did not extend the micro-entity discount to embrace the significant fees of the new AIA post grant proceedings.