How to detect page type

Hello

I asked this on IRC but as nobody answered, here is the question, so I
can go sleep and check the answer tomorrow.

I am designing a theme. I have a template for the main page. I would
like to make the template larger if the page is in "edit" mode. Is
there any variable I can query to check the "page type" at run time?

Thanks
Cheers
ambs aka Albie

--=20
Alberto Sim=F5es