Recordable DVD Information Needed

Could someone please define everything to do with Recordable DVDs?  What is the difference between the X#s?  What is a layer?  Etc etc etc.

 

How do I find out what the maximum size disk my DVD Recorder will record?  What is the maximum X#?  I need help learning all of this before I go out and buy software with which to record.

 

I don't want to buy software that I don't need or can't use.  I don't want to buy disks that I can't use.

 

I am very confused with all of this.  The newest recordable media that I have been introduced to before this was the Iomega drive, and I thought that was the best thing since sliced bread.  I have since had my rosy glasses removed, since it seems that the Iomega never really caught on anywhere to my chagrin.

 

If there is a website that goes into detail with this information, I will gladly take that in leu of someone typing up a long detailed explination here.  All I ask is for a novice level introduction and explination.

 

Thank you.