A PAC (Political Action Committee) is a group of people who come together, throw their money into a pot then donate the money to candidates who reflect their views.
Most PAC's employ a lobbyist, who monitors pending legislation and tried to educated and influence elected officials to vote according to the wishes of the PAC.
There are Conservative PACs and Liberal PACs. PACs are not totally Bad or totally good, neither are lobbyists.
Is that what you were asking?