I want to place something like
Cart: X Items
in the header of each page, where X is the total number of items currently in the cart.
 
I know where to add the code (as far as the block and template I'm using), but can anyone help me with the code needed to retrieve this value?
 
Thanks!

I did post a solution however I remembered that I customized the code more than I thought and as such it didn't make sense for a vanilla install:/
 
Feel free to contact me if you want it done.