It has also been rumoured that iPad 2 will have a dual core processor, dual cameras and USB port and SD card slot. It apparently will also have a resolution of 2048 x 1536. This is still unconfirmed and some reports have contested that the particular resolution will be seen most likely in the iPad 3.
If you have a iPad 1 its probably not worth upgrading unless you are an early adopter or you cant just stop yourself ! The investment in the 2 will show some relative enhancements but it all depends on what you use it for.
If however you havent bought an iPad 1 yet - then dont !! Wait the few extra months !