Partitioning Problem - The limit of 4....

Hello I'm up against the 4 primary partition limit on a SATA drive, but I want to install an additional distro. Now, I have a dual boot system: XP, Ubuntu. I've used EasyBCD to create the boot menu. This is my layout: C:\ --Primary Partition 1: XP --Primary Partition 2: Ubuntu root --Primary Partition 3: Ubuntu swap --Primary Partition 4: Ubuntu home I'd like to install another distro to the C:\ drive, but I already have 4 primary partitions, which is the limit. I have plenty of unallocated space on C: which I reserved for another installation, but now I realize that I'm up against this partition limit. I want to preserve the Ubuntu installation. So, is there a way to convert one of these primary partitions to an extended partition into which I can add more logical partitions? How? Is there a simpler alternative? Partitions 2 - 4 were originally created with gparted during the Ubuntu installation. Windows sees the drive with 4 primary partitions and unallocated space, but Windows will not allow me to create any more partitions. Any hints would be appreciated. Oh, and I'm a newbie, as if one couldn't tell. Thank you