Unfortunately, with the exception of the libertarians, its hard to see who is what without a score sheet.
If you go waaaaay back, to the late 1700's or so, a liberal of the day would have more in common with a modern libertarian. Nowadays that's quite obviously not the case.
In the more modern era, say the 1920's to the late '70's, early 80's conservatives were typically marked by being resistant to changing things, as well as adherence to the concept of 'that which governs least, governs best.' In other words, fewer taxes, less government intrusion. Liberals of the era were marked by policies advocating bigger government and higher taxes.
Currently, conservatism is deader than disco and has been replaced with neo-conservatism, which espouses many of the ideals traditionally held by conservatives, but generally involves massive government spending to realize those ideals.
In other words, neo-cons don't see massive governmental growth as a bad thing, which would be a concept considered anathema to traditional, or old-school conservatives.
Examples of each:
Old School liberals- Locke, the Founding Fathers
Modern liberals- Hillary Clinton, Charles Schumer, John McCain
Traditional Conservatives- Barry Goldwater, Ronald Reagan, Florence King
Neo-Conservatives- Joseph McCarthy,* Jonah Goldberg, John McCain, George W. Bush
libertarians- see old school liberals**, Rep. Ron Paul, P.J. O'Rourke, Ludwig Von Mises, Murray Rothbard
In the end, labels such as 'conservative' or 'liberal' tend to be very fluid.
*McCarthy could possibly be seen as an embryonic neo-con.
**Obviously the founding fathers might not agree with every conclusion drawn by modern libertarians, but they certainly have more in common with them than any other currently flouted ideology.
