all ready / already

1. "After 3 hours of putting on cosmetics, I was all ready to go swimming."
All ready = used as an adjective to express complete preparedness.

2. "Once I arrived at the pool, everyone had already left. I guess the party started at 10 AM, not 10 PM."
Already = an adverb expressing time.

all right / alright

1. "Is it all right if I just leave you down here?" asked Rose to Jack on the sinking Titanic, after many failed attempts to free Jack from being cuffed to the pole.
All right is the correct spelling.
Alright is used informally.

all together / altogether

1. "After looking into Britney's wallet, we found there were ten maxed out credit cards all together."
all together = an adverb meaning considered as a whole, summed up.

2. "The credit cards are a problem...but marrying K-Fed is an altogether different issue!"
altogether = an intensifying adverb meaning wholly, completely, entirely.

anyone / any one

1. "Anyone is allowed to sit at the Cheerleaders' table. (Anyone meaning if you are skinny, preppy blonde.)"
Anyone = a pronoun meaning any person at all.

2. "Any one of those people could have won "Most Gullible" for Standouts."
Any one = a paired adjective and noun meaning a specific item in a group; usually used with of.

maybe / may be

1. "Maybe you should wait for the lightning to stop before water skiing in the lake?"
Maybe = an adverb meaning perhaps.

2. "This may be my only chance at stardom!" yelled a contestant to Simon Cowell on American Idol.
May be = a form of the verb be.