Howto or crib for backing up two tape drives - amanda 2.5

[chuck.amadi]

Hi Is there doc's for setting up ainternal and extrenal  tape drives As 
I have a DDS-4 drive and need to commission a second external drive to 
backup a total of 80gb server and I would like to backup a minmum 300gb 
eventually I was looking at LTO-3 but it is beyond my companies budget.

I read a email not long ago stating whats new for version 2.5.0 and 
there something about having amanda backup two tape drives which would 
be ideal for my situation when the first tape drive is full it would 
continue without admin intervention to the second drive.

Please could someone point me in the right direction as my monthly 
backups are nearing the full capacity of the tapes which are 20gb native 
DDS-4 4mm * 150mm.

Cheers