I'm thinking of splitting my only harddisk into 6 partitions and forming 3 RAID devices for setting up of RAID0. Will there be a speed boost this way?

If i'm using two harddisk, is it necessay to put the two as masters on different bus to achieve speed boosts?

My first question... Why? RAID stands for Redundant Array of Independant Disks. If you have one hard drive, even if you set it up as 6 partitions you don't truly have a RAID. RAID 0 would only provide a performance boost if you had multiple disks.

As far as the question about using two disks, to get the maximum speed you would definatley have to have them on seperate IDE channels since IDE can only read/write one device at a time per channel. I don't know if you would get any increase in performance if you set them up as Master/Slave on the same channel.

No. Thats a horrid idea. The way RAID speeds up data acess is spinups and searches for data on the second drive can be done and data read into memory while the first drive is sending out it's data. If it could be done, using RAID on one disk would most likley slow things down, as it would have to search further into the disk to get parts of data than normally. You'd basically be setting up a "fragmented" disk that could never be defragged.
No, but it helps.

I realize you are probably on a tight budjet, but if you want to get into RAID on Linux you'd be best off buying a 3Ware raid card. They rock. Here's a URL to what I have.

http://3ware.com/products/parallel_ata.asp

Thank you everyone, the advices helped in my understanding. And you were right i am on a tight budget