Add user points for every up vote
Theres is a module to add rules to voting api: http://drupal.org/project/voting_rules

Userpoints comes with native rules support.

I just set the whole thing up on my test environment, added a new Rule with

Event: User votes on a Node

Condition: User has role(s)
Parameter: User: [vote:user], Roles: authenticated user

Condition: Check the value of the vote
Parameter: Vote: [vote], Operator: is greather than, Data value: 0

Action
Grant points to a user
Parameter: User: [vote:user], Points: 5, Points category: General, Operation: Insert, Moderate: Use the site defaul


additional info:
you must enable userpoints and userpoints_rules as well as voting_rules

Here's the export of the rule

{ "rules_reward_voter" : {
    "LABEL" : "reward voter",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "rules", "voting_rules", "userpoints_rules" ],
    "ON" : [ "voting_rules_insert_node" ],
    "IF" : [
      { "user_has_role" : { "account" : [ "vote:user" ], "roles" : { "value" : { "2" : "2" } } } },
      { "voting_rules_condition_check_vote_value" : { "vote" : [ "vote" ], "operator" : "\u003E", "value" : "0" } }
    ],
    "DO" : [
      { "userpoints_action_grant_points" : {
          "user" : [ "vote:user" ],
          "points" : "5",
          "tid" : "0",
          "entity" : [ "" ],
          "operation" : "Insert",
          "display" : 1,
          "moderate" : "default"
        }
      }
    ]
  }
}