so my friend has the iphone 3g and he jailbroke his so i wanted to kinda do the same so i unlocked my blackberry what are the benefits from unlocking it?

Able to use on different carriers and overseas - not tied to one single carrier. Assuming this is a GSM BB. If it is a CDMA one, you can't unlock them.

You can unlock any BlackBerry if you get the codes from the carrier. The challenge is getting the codes from the carrier. There is no benefit to them in unlocking the phone for you to switch carriers so they usually wont give you the codes.

Wrong.

Most GSM carriers will give you the codes, often with certain requirements such as the account is in good standing and you have been a customer longer than 90 days.

Even then, if you ask, you often get the unlock code if you simply explain you are traveling overseas and need to use the device elsewhere while traveling.

EVEN STILL--you can purchase the code, cheaply, from places like HorizonWirelessOnline.com - Horizon Wireless, The World’s Cellular Repair Center ß

Not in my experience. I've received quite a few subsidy unlock codes directly from TMO and at&t.