Everybody’s loving iOS 4.2 for iPad: it brought multitasking to the tablet, folders, AirPlay (sort of) and, ehm, AirPrint. We have already talked about this. As more users upgrade to the new iOS every day and jailbreak it using the latest version of Redsn0w, they need really a list of compatible Cydia apps and tweaks.
MuscleNerd of the iPhone Dev Team has published a spreadsheet on Google Doc showing the compatible Cydia apps, you can navigate to this link to check the list of apps & tweaks in Cydia compatible with iOS 4.2.1. If the color is green that means it works with no problems, if it's yellow it means that it have some problems. Any you know, red ones are unusable and not working. The list should be upgraded consequently when an app gets iOS 4.2.1 compatibility.