What is the difference between CMDA, GSM, P1000L. and P1000N? I'm looking to root (cyanogenmod) a Galaxy Tab I have lying around. Looking on the CMG site, I see that there are 4 different versions: GSM, CDMA, P1000L, and P1000N.

What are the differences between these? And how can I tell what version my tablet has?
GSM and CDMA refer to the 2G/3G cellular technologies used by phones and tablets.  In USA, AT&amp;T and T-Mobile use GSM, while Sprint and Verizon use CDMA.

GT-P1000L and GT-P1000N are variants of the international Galaxy Tab GT-P1000 version that were released by Samsung for Latin America markets.  Both P1000L and P1000N models have GSM connectivity.  You can find the exact version you have in Settings -> About under the Model number section.

In terms of rooting and installing CyanogenMod, you will need to refer to the CyanogenMod wiki for the respective model (P1000L or P1000N).