1. Missoula County Election Officials : You'll find sample ballots and voting rules. Go to their office at the county courthouse and you'll find campaign finance reports for legislative and local races. This is the place to be Election Night for results. After an election, you can find out who voted.
2. Secretary of State: Oversees state voting process. They publish an voters guide too.
3. Federal Campaign Cash and Donors: The Center For Responsive Politics` tracks donations in races for the U.S. Senate and the U.S. House of Representatives. Watch the dates, though. You could go straight to the Federal Election Commission too.
4. 527 Committees: These organizations produce advertising apart from the campaigns. The messages are clearly slanted , but they're careful not to tell you how to vote. An outfit called Source Watch tracks them. So does opensecrets.org.
5. State Campaign Contributions: Records for donation to statewide races and ballot issues are kept by Montana's commissioner for political practices. Nothing on-line yet.
6. Project Vote Smart: Lots of information here. You'll find candidate bios, links for campaign finance info, voting records, positions on issues. You'll need to verify this stuff, though.