Oracle Database Discussions

Hi,
I'm working on archiving huge production data. Can somedody suggest some of the best ways of doing it. I'm basically looking for something that doesn't take too long to archive.

Is there a document that gives the pros and cons of using Trasnportable tablespaces vs External tables.

I was reading about external tables and I'm not quite sure how we can use it to archive data. I mean the steps I read mentions create flat files. Now how do I get these flat files out of the production data. The production data has data in one tablespace, indexes in a seperate tablespace and LOB segments in a seperate tablespace.

Any help would be greatly appreciated.

Thanks,
Mamata