I believe kernel version 2.6.33 and later fully support the i3 (including the IGP). Version 2.6.32 (a patched version of which is used in Ubuntu) will probably support the processor but the IGP may not work.
It's a question of the Integrated Graphics Processor. As randomizer says, this is not supported - or certainly not fully supported - on pre-2.6.33 kernels. Many distributions have not yet updated the kernel to this level. (Of course you could always download, configure, compile and install a 2.6.33 kernel, but this can be a bit intimidating for some users.)