Making page adapt to monitor resolution

[couponsitescrip]

I have a to make web page containing 2 columns. This is done.
Now what I would like to insert in the code is something like this:
The 2 columns should be full screen on any resolutions. Something like the page would adapt to the monitor resolution.
The percent would be 80% for the first column 20% for the second one.

What I don't know - is how to do that. Would a table resolve this problem?
What would be the code for this?

Suggestion are well appreciated.