If you're reading this, you're probably aware that Google publishes Android as an open-source operating system, allowing anyone to modify the code, customizing it for different devices or ROMs. What you may not know is that all the Google apps on certified Android phones, like Gmail, YouTube, Goolge Calendar, and of course the Android Market, are closed-source, and can't be modified without breaking Google's copyright. Ever since Ice ream Sandwich ROMs started popping up, ROM flashers have been using some cobbled-together Google Apps packages that are decent, but sometimes lacking new Ice Cream Sandwich features. Now a new and unofficial Gapps.zip package is available for CyanogenMod 9 and other Ice Cream Sandwich ROMs.
You can see the updated ZIP file at popular ROM file hosting service Goo-Inside.me. This is apparently different than the KeJar Gapps package, which has been the de-facto standard for the last few months. Since nothing's changed on CyanogenMod's Wiki page, all bets are off on functionality and compatibility. Flash a new ROM on your phone or tablet via a custom recovery, then flash the "gapps-ics-20120207-signed.zip" file, and you're done. Google's apps aren't necessary for running Android, but most users in the US and elsewhere consider them an essential part of the Android experience.
Now for the downside: you can't just flash the new Gapps package over your existing one. Unless you've never flashed a previous version of Gapps on your existing Ice Cream Sandwich ROM, you have to wipe your personal data first. If you don't the apps will force close upon opening, and you'll be pretty much jammed as far as all the included software is concerned. For that reason, you might want to wait until your next major ROM update to do so. As always, make a Nandroid backup before flashing any new ROM or mod.