No there is no specific place on this site that does this, but I will attempt to anyway.
GB is a unit used to measure the quantity of memory a computer has either RAM or HDD or VRAM. All of these are different forms of what is ultimately 'memory'.
1000GB=1TB and that's probably the main units you need to know about.
For example when the specs of a Macbook Pro states the following:
750GB, 5400RPM - That is referring to the HDD space and the speed at which the hard drive can spin to find information.
4GB 1333Mhz Memory - Is referring to the amount of RAM a computer has.
1GB VRAM/GDDR5 is the amount of memory that the graphics card has dedicated to it.
MHZ/GHZ is a measurement of clockspeed, the raw ability of a computer to process information. A higher Clock Rate (GHZ/MHZ) the faster a computer can be (crude, I know as there are many other factors such as Cores and Cache etc).
The more Cores a computer has, the more effectively the computer can multi-task. Most i7's have what is called 'Hyper-Threading' which makes the computer see 8 cores as opposed to the 4 physical cores. This enhances the multi-tasking ability of the computer further.
If you have more RAM, you can theoretically handle more tasks at once.
More Video RAM, theoretically the same thing, more graphics potential.
Still, do more research but if you have more questions, please ask.
No-one knows when the next ones will be released, I personally think Apple will start getting shipments of Ivy Bridge CPUs in early April, and we will see them about a month later. Even thought they have a few Ivy Bridge CPU already.