It is not necessary that every time you buy a sim card you have to buy a new mobile set. In fact, all the GSM service offer the option of buying only new Sim card, be it pre-paid or post-paid. The services providers these days are offering " sim only plans" that says that you don't need to change the handset to change your number.
Most of the telocom companies are going for the option called as " sim only contracts" which means the contract is only related to the sim that use without any concern of what handset you are using. This makes a customer free to use his handset or buy new if he wants.
There are a number of reasons for which a customer may need to buy a new sim card, or we can need to change his sim card for new number.
the various reasons are:

1. change of geographical location
2. customer needs to change du e to connectivity issue
3. to opt for better mobile rates with different sevice provider.
4. for security issues
5. due to change of job that may require to follow company policy.

Whatever be the reason, one cannot afford to change the handset every time.

There are various service providers in market that offer easily change of SIM without changing the handset. To name some you can visit : http://www.simonlyoffers.com/

These websites give you a lot of idea as how to change your sim card without changing handset.

The Nokia 5330 Mobile TV edition launches today, ushering in a new era for Mobile TV. The stunning-looking device is sure to drive appeal amongst the 300 million people expected to be watching mobile TV around the world by 2012. The 5330 isn’t just about Mobile TV though, this 3G speed machine also packs in the latest in social networking, music and gaming in one sleek slide-design.

Based on DVB-H technology, the Nokia 5330 Mobile TV edition sports a 2.4-inch screen for super sharp images on the move. The headset doubles as an antennae for clear reception and together with Nokia’s own Electronic Programme Guide (EPG) it makes watching TV on the move a joy.

The device also packs Nokia Messaging so users can keep on top of email and Instant Messaging, the latter supporting Windows Live Messenger, Google Talk, Yahoo! Messenger, ICQ and AOL amongst others. Pictures are taken care of by the 3.2-megapixel snapper, whilst dedicated music keys take care of the audio side of things. It’ll also sport links to Nokia Music Store, where available and the device is also compatible with Comes with Music.

No need to worry about the 5330 running out of juice before the final whistle either. With six hours of battery for TV watching, you’ll be able to watch a couple of matches and still have time for a few calls. Standby time runs to about 14 days on this series 40 based device.

More than 30 operators around the world are rolling out Mobile TV services now, with Austria, Finland, Ghana, Kenya, India, Italy, Namibia, Nigeria, Netherlands, Philippines and Switzerland all boasting services. It’s expected that another 20 countries will be offering mobile TV within the next two years.

The Nokia 5330 Mobile TV edition will retail for €155 before taxes and subsidies.

Nokia is strengthening its CDMA portfolio with the announcement of three new CDMA mobile devices: Nokia 6316s, Nokia 3806 and Nokia 1506. Together this new line-up highlights Nokia's continued commitment to CDMA as a major standard in key markets around the world.

"Nokia is boosting its leadership in the CDMA market by updating an already strong line-up with products that appeal to a wide range of customer needs," said David Tang, Vice President of Nokia China.

Nokia has launched 3 new CDMA Mobile phones. One amongst them is Nokia 1506 CDMA. A simple and easy phone to handle and carry.