Grammar Girl does a good job of explaining the difference here.

“a while” = noun
“awhile” = adverb

Thank you.

:)

http://motivatedgrammar.wordpress.com/2008/01/14/inner-spaces-iv-its-been-a-while/

“Let’s stay awhile.” Adverb modifying the verb “stay.”
“Let’s stay for a while.” Noun, object of the preposition “for.”

I imagine this distinction is destined for oblivion in relatively short order, considering how frequently these days I see constructions such as these, here on fluther and elsewhere:

“I’d like to be apart of the group.”
“That’s going to take along time.”
“Can you find away to help me?”

@Jeruba I must agree with you. The mutilation of the English language is ridiculous and disheartening. Just my opinion.

Like how “on slæpe” became “asleep”, “to morwen” became “tomorrow”, “for ever” became “forever”, etc.

@Jeruba My eyes went over three sentences, reading the meanings rather than the words. I guess that’s what happens when you have to hear the words you read. I’m sorry to think they aren’t just typos. It’s hard to recognize that your own language is changing without resenting it.
I liked it the way it is! Don’t mess it up!