In a brief nutshell, today's Republicans (the Good Old Party, GOP) are characterized by a want for 'smaller' government, a more agile (not necessarily bigger) military, and a connection with (usually religious) blue-color 'everyman' workers. They believe in a government that is reflective of overarching, 'home grown' family values, as can be best seen in their "Contract With America".
Democrats are more for creating a social welfare society, and believe that government should play a more active role in daily life (though not necessarily intrusive). Many people brand this party as being 'liberal', which is actually a fairly new designation considering many Democrats (also known then as Dixiecrats) were opposed to 'liberal' civil rights reforms in the 1960s. Further, whereas Republicans target typically older citizens,
Democrats tend to lean towards younger, educated professionals (for example yuppies) and are a favorite on college campuses. Unfortunately, in today's America politics has become frighteningly divisive. We can't even have a hurricane (I cite Katrina) without people pulling out 'Republican this' or 'Democrat that'. Further, the two parties aren't helping the matter either. Whenever someone does something wrong (For example a Republican President or Democratic governor), it is suddenly the fault of the entire party, and not just that one person.
You seem educated enough to visit each party's website and read their platform. Skip over anything with the word 'Iraq' or 'terror' in it (because these are in the spotlight, and are likely to be uselessly full of propaganda) and instead read your opinions on issues that effect your daily life, such as public education, health care and taxes. I think you (and many other people) would be surprised at how much the two parties actually agree on, but with different routes.