A little and little refer to non-count nouns, and is used with the singular form:

Examples:

There's little wine left in the bottle.
I've put a little sugar into your coffee.

A few and few refer to count nouns, and are used with the plural form:

Examples:

There are a few students in that classroom.
He says few applicants have presented themselves.

A little and a few convey a positive meaning.

Examples:

I've got a little wine left, would you like some?
They've got a few positions open.

Little and few convey a negative meaning.

Examples:

He's got little money left.
I have few friends in Chicago.