Take a look at Tipsheet #116, a one-page source list of government office contacts that have Information on lobbying activities.
Tipsheet #100 provides state-by-state listings of agencies that administer ethics and lobby laws.
Another helpful tipsheet regarding lobbyists is Tipsheet #923, "Lobbyists and local elections," from the 1999 National CAR Conference.
All tipsheets are available online at www.ire.org/resourcecenter