When I send a text message to a friend of mine, a different friend's name comes up. Why would this happen? How do I fix it? This is on a Blackberry Curve.

Its just a connection problem, probably due to the area your in and interference. Does your friend receive calls fine when this problem occurs?

This issue only occurs when trying to send a SMS text message from within the call details screen of a call in the call log.
To avoid this issue, complete the following steps to send a SMS text message from the call log screen:

1. Open the Phone application.
2. Open the Call Log by clicking the middle button in the toolbar.
3. Touch the call log/contact in the list without clicking the screen.
4. Display the menu, then select SMS Text (Name/Number).
5. If required, rotate the BlackBerry smartphone to switch to landscape mode.

Pull the battery out while the phone is still on, wait 30 sec. to 1 min and then put it back in, should solve the problem.

*Mine has done the same thing 3 times so far, just keep pulling the battery out and put it back in until they figure out what the issue is and make a fix.*

check to see if u have enabled support for special characters (characters other than numbers and alphabets) for text messages... i think u have to enable Unicode support in your piece,
Either that or the configuration may not be correct in sender's piece (it means you are receiving SMS from other senders properly )

First, I assume you have a service provider, a valid cell phone number and that your service provider has enabled text messaging as part of your plan.

To send a text message, go to "Messages", then click "Compose SMS", "[Use Once]", "SMS".

Type the cell phone number of the person you want to send the message to.

Click the trackwheel, then "Continue".

Type a message.

Click the trackwheel.

Click "Send".

If you still are not able to send a text message, you need to verify that "fixed dialing mode" is not enabled. To do that:

Go to Phone Options.

Click "FDN Phone List".

Click the trackwheel.

Click "Disable FDN Mode".

Go into a new text message and hit the "send to" option. Scroll down to the first name above the line and hit the "options" button. Scroll down and select "Recent messages" and choose whoever from that list that you'd like to be your top 3. I actually just sent all three of mine a blank text, but when I went back to the "send to" list voila! MORE INFO: I tried all kinds of things to remove names from my top three recipients list. What ended up working was to send a text to multiple recipients at once. Two was enough. But it was important who I selected first. I sent a message to my wife and my friend. My wife's name got added back to my top three! Then I reversed and sent a message to my friend and to my wife. His name got added back!

Go into a new text message and hit the "send to" option. Scroll down to the first name above the line and hit the "options" button. Scroll down and select "Recent messages" and choose whoever from that list that you'd like to be your top 3. I actually just sent all three of mine a blank text, but when I went back to the "send to" list voila! MORE INFO: I tried all kinds of things to remove names from my top three recipients list. What ended up working was to send a text to multiple recipients at once. Two was enough. But it was important who I selected first. I sent a message to my wife and my friend. My wife's name got added back to my top three! Then I reversed and sent a message to my friend and to my wife. His name got added back!

Go into a new text message and hit the "send to" option. Scroll down to the first name above the line and hit the "options" button. Scroll down and select "Recent messages" and choose whoever from that list that you'd like to be your top 3. I actually just sent all three of mine a blank text, but when I went back to the "send to" list voila! MORE INFO: I tried all kinds of things to remove names from my top three recipients list. What ended up working was to send a text to multiple recipients at once. Two was enough. But it was important who I selected first. I sent a message to my wife and my friend. My wife's name got added back to my top three! Then I reversed and sent a message to my friend and to my wife. His name got added back!

My operator said it could be due to having two or more same phone numbers saved under different names.

However, mine wasn't a case of having same numbers under a different name. But after a few days it became fine. The problem resolved by itself even though I didn't specifically do anything to correct it.

Well, I guess this is a common problem with smartphones. It happened to my Dad's N70 and my friend's Ozone too. Don't worry too much about it.