Potential 2010 Senate candidate Pat Toomey will make an appearance at a key conservative activists' dinner tonight, perhaps laying groundwork for a campaign.

Toomey will be the keynote speaker at the Pennsylvania Leadership Conference taking place in Harrisburg, Pa. this weekend.

The conference will host what it asserts on its website is a record number of conference attendees in central Pennsylvania, as Toomey mulls a primary challenge to Sen. Arlen Specter (R-Pa.).

Toomey had challenged Specter from the right in 2004, and would again wage a conservative challenge should he run again.