Ford Escort A/C Blowing hot air!!?

I am mechincally challenged but the air conditioner on my 1998 Ford Escort has stopped blowing cold air. The blower is fine it pumps out on full, but the air is warm to hot. I am wondering if it the freon? How would I check its level? Or could it be the compressor? Any help is greatly appreciated as it is about 90+ today!!