I don't use Mandriva either, but I have partitioned about 20 computers' worth of hard drives, both dual-boot and Linux only.
By default, Linux uses three partitions. They are the root (/) partition, the boot (/boot) partition, and the swap area. Both root and boot partitions are formatted EXT3. From what I've read, the biggest reason for the separate boot partition used to be some necessary protections during the boot process, but now it is mainly historical. Either way, when comparing the size of the boot partition to the root partition on large, late-model hard drives, boot is insignificant.
I guess you could do away with the boot partition, but in general I think it is bad policy to change a default unless you know exactly what you are doing and why. My suggestion is to leave it there unless you have an overriding reason to delete it.
I've used Ranish partitioning software with good results, but I'm generally starting with brand new or zero-filled hard drives. Google for it.