America Online is planning to launch by the end of the month AIM Phoneline, a free service that will let AOL Instant Messenger users receive incoming calls from any phone, an AOL spokeswoman said Thursday. Voice over instant messaging is built into AIM, Google Talk, Yahoo Messenger and MSN Messenger, but AIM Phoneline would be the first to offer a free phone number. Those services compete with the popular net telephone provider Skype, which was acquired by eBay last year.Users will be able to pay $14.95 a month to upgrade to AIM Phoneline Unlimited, which would allow them to make calls to any number in the U.S. and 30 other countries, the spokeswoman said.