How on earth do I remove a partition?

So, I have a shiney new macbook and already made my first mistake For reasons I won't go into, I used Disk Utility to create two separate partitions and now I desperately need to get back to just one. I'd have thought it was simple but apparently not. I've tried:

Re-installing from the install disk - all this does is ask me which of the 2 partitions I want to install on :-(

Using Disk Utility - I can see no way of removing a partition here.

If anyone has any ideas I'd be really grateful - there is nothing on the machine yet so it doesn't matter if I have to reinstall.

Thank you!!

First you need to boot from the install media. Once you have done that, under one of the drop down menus, you will find disk utility. Select it. Then you select the disk that you want to work on. You should see five buttons (First Aid, Erase, Partition, RAID, and Restore). Choose Partition. You should see your two partitions. Under the Volume Scheme there is a drop down menu. Select 1 partition from the menu. Also select the Mac OS Extended (Journaled) format. hen click on the Partition button. After you have down that, do a clean install of the OS.

Also placed this in the proper forum.