Do SSD's heat up?

No; they are not mechanical devices so only the electronics use power. When idling most SSDs use less than 1W and often in the range of 0.1W, while normal 7200rpm HDDs use about 6-8W and the Green drives about 4-6W.

When fully stressed, it may consume little over 1W, but still does not come close to anything regular 3.5" desktop drives consume.

SSDs should never need any cooling. It should also be safe to use them in extreme temperatures; unlike HDDs which are extremely susceptible to temperature changes and diminishes their lifespan.

no, do not worry about it, SSD has a better performance than mechanical devices.

Generally speaking, the less watts that go in the less heat that should come out.

Since the power consumption is 99.9999% converted into heat that's the general idea.  

So power consumption equals heat generation. The actual temperatures depend on how well this heat is dissipated and the amount of surface available to dissipate.

So they dont need passive cooling? I havent seen computer cases that can dock SSDs stock...... Thus I take it they should last alot longer than HDDs?

They last longer than hard drives under some usage patterns, but shorter under others (especially heavy writing). They are unlikely to die from heat though.

The spec sheet for my 1TB Western Digital Caviar Green drive reads:
Temperature (Degrees C) - Operating 5 to 55, Non-operating: -40 to 70

The spec sheet for the Intel X25M-G2 drives reads:
Temperature - Operating: 0C to 70C, Non-operating: -55C to 95C

The power consumption of the Intel SSD is 75mW (0.075W) idle, 150mW typical

5 to 55? That's different - most HDDs that I know of are rated 0 to 60. Not that it honestly makes much difference...

Interestingly, the 2GB Green is rated 0 to 60C, but the 1GB is 5 to 55...