Want to use another sim card in my phone it requires special code can u help me to solve the problem

i think your phone is asking for unlocking code. you can get the special code for your sidekick slide from Classicunlocking.com

PUK stands for Personal Unblocking Key. This is a uniqueeight-digit code specific to your SIM card. This is required when the PINnumber to unlock your mobile phone is entered incorrectly 3 times. You are thengiven 10 attempts to enter your PUK code. If an incorrect PUK code is enteredafter the 10th attempt, you will block your SIM card permanently and willrequire a new SIM card from your mobile phone provider.
PUK codes can be obtained through the following ways - The PUK code is in your SIM card documentation Starter Pack.If you do not have this then -Please contact your phone service provider.
Your cell phone service provider can give you the PUK code once you give themyour account details and they have confirmed your identity.

Well if you are tied to a particular network all you have to do is to unlock your phone to use it any other GSM network. You can get the unlock code through online. Give your IMEI number & get the unlock code for ur mobile .............You also get through online..........I will suggest the website Unlock-Zone.com which is doing good service .....you can approach this website.

xda-developers.com will be your best chance of sim unlocking the sidekick

although boost is a ppd version of nextel, the sims cards are different and are not interchangeable between devices........you can contact SprintNextel and they will give you the "subsidy unlock" code, which is the special code required for your device to stop looking for a specific sim card. If they wont give you the code then you can google "motorola instant unlock" or whatever brand device it is and chose from the large list of web services that can send you the key for just a few dollars. GOOD LUCK AND PLS RATE THIS POST!!!!!!!

Either the sim card is not activated or the card is not for this phone and will require the sim to be unlocked which many websites offer to do for about $5

The code is the unlock code. It must be unlocked to use with the digicel network. Contact T-Mobile since they manufactured the phone and they will provide the code to you.

Your phone may state that you need the "special unlock" code but there is no such thing. This issue is rarely solved by powercycling the phone. In many cases the cusomer will have to take the phone to the nearest service and repair center for an exchange.

just ask the phone company provider for your PUK2 AND PUK codes.
when you get them go to the jump menu dial
**05*PUK*passcode*passcode#
the passcode is any 4-8 digits you'd like, that are NOT, AND I REPEAT N - O - T consecutive.
(for example 2736 is good whereas 1234 or 9876 is bad)
if it asks your for the code again put in the PUK2 then go to settings> network options goto the "scan and select manually" button and chose your carrier.

I need the IMEI (International Mobile Equipment Identity) number. Type this code in your phone to get it: *#06# you can also find it beneath the battery.
I also need to know the make and model of phone, the network that the phone is locked on, and the country the network is from. Then I will give you the codes. If this is what you want.

SIM pin code:
This is a pin code that locks the sim card until you enter the correct code. This protects your account, even
if your sim is put into another handset. To reset it, you need the PUK code:
Pin Unlock Code (PUK)
If you miss key (or forget) your SIM pin code, and enter the wrong one 3-5 times in a row, the SIM will lock up, and you’ll need to enter the PUK unlock code to release it. You should ask your Network Service Provider for this code when you need it. Don’t try to guess it, because after a few wrong guesses, the SIM card will be permanently disabled.
Phone Security Code:
This locks the handset, as opposed to the sim card. You can also set some handsets to only accept a “new” sim if the phone security code is entered. To reset it, you need the Master code code:
Master Reset Code
Sometimes known as the Master Code, this allows you to unlock a handset if you have entered the Security Code wrongly too many times.

Special Code/Service Provider Lock Code:
This code is required to allow a phone locked to a particular network's SIM cards to be used with a SIM card from another network. The unlock code varies from individual Handset to Handset, and Network to Network.
Which is the one that you want?