Help me please for the love of God.

This is the only thing to do with memory specifacations that I just don't understand. On Corsairs website they have "Ram Type" as the heading of a column for lets say a 256MB DDR PC2100 ram, they will be exactly identical except one is "16Mx8" and the other "32Mx8" I'm guessing it means one is double sided and the other single sided. Is this correct?

If so, which is better? Why? Would they both generally be compatible in the same motherboard?

It's the amount of memory per chip. 32mx8 would take 8-32 bit chips to equal 256mb.
16X8 would take 16-16bit chips to make a 256mb stick.

So if both are 256mb sticks the 32X8 one will probably have 8 chips on one side or 4 on two sides and the 16x8 will have 8 chips on each side.