Charitable donation only shows up in Schedule A. So you have to use itemized deduction to claim it.

What SPRING100 said was pretty accurate except that, starting from 2005, you will need to keep a statement from the donee for every donation that is equal or above $250. But remember, that's a requirement for book keeping. You don't need to file the statement with the tax return. You just need to keep it.

In Column 1, Page A-7 of the Schedule A Instruction, the IRS explicitly says that:

In figuring whether a gift is $250 or more, do not combine separate donations.

So you don't need any paperwork at all. But of course, it is always a good practice to write down some notes on the nature of the donation, and keep the receipt. :)