First, DO NOT directly drive it with the microcontroller without knowing more. The output of the microcontroller (any microcontroller, not just MSP430) can be damaged driving the inductive load and current demand of the relay coil if not done properly.
That said, it is tough to give details without having the part number for the relay, so I will give some generalities:
The recommended way to drive the relay is to use a transistor (an npn bipolar is traditional) as a switch to ground, and use a diode across the coil to shunt the inductive kickback when shut off. Directly driving is likely to damage or destroy the microcontroller, sooner or later, even with a protection diode. Not a guarantee, but, again, without part data, I would lean that way.
A six pin SPDT relay could be the same as a five pin, with one unused or a redundant connection (often the common for the switch), or could be a double coil. Need to know what the model is. A double coil is generally a unipolar latching type: trigger one coil to latch to the NO position, the other to release to the NC position. Gotta look at the data sheet to see if coil current polarity matters. Some do, some don't.
