I want to dual boot Gentoo and Ubuntu. So i'm installing Gentoo first. I want to set up my partitioning scheme

I'm not concerned with sizes and such all I really want to know is if it's ok to leave the rest of the drive as part of hda3. Can I come back later and finish chopping up hda3 or do I need to do it now? Will paritioning up the rest of hda3 later destroy the data on the other paritions?

hda1 thru hda4 are primary partitions. You can only have four primary partitions on a disk. Of these four primary partitions, one of them may be designated an extended partition. Within this extended partition, you may have 63 (64?) logical partitions. Logical partitions are numbered starting at "5" and going up from there (e.g., hda5, hda6, etc.) The extended partition cannot be followed by any more primary partitions (this in reference to physical layout on the disk, not the order of entries in the partition table, which can vary).

So your current setup would allow you to create more logical partitions at a later date (providing you have unpartitioned space in that hda3 extended partition). But you could not create any more primary partitions unless your unallocated space happens to fall (physically) between your current hda2 and hda3. This is probably not the case, unless you specifically partitioned to keep the middle of your disk free. Not that this makes any difference to Linux. Linux doesn't care about this primary/logical thing like Windows does (and Windows can be coerced into "not caring" with a little effort).

Short answer: Yes, you can chop up the remaining free space in your extended partition at a later date. (Just don't plan on installing Windows there, without some work.)

Sweet. Thanks alot, thats all I needed!