Right I only deal with Nokia's personally, so not 100% about other brands, but that said it does seem yours is possible to unlock, but the best method for you will depend on your sp (service provider), some are real jobs worths, others are as good as gold, many a time it will depend on the person you talk to, hence not being able to say specifically whats best for you.
There are 2 options for you, first is your sp, this is best "IF" they play nice, my hope is that if you tell them your going abroad and can't use they're service there (need to know your phones operating frequency's) that they would then give you the code for free, BUT, if you are tied into a contract or have any obligations to fulfil with them, odds on they wont help, not unless you pay whatever your obligation is to them.
The other possible is to find a friendly assistant in one of their shops, see if they will help, might be easier in person, failing that your reduced to a 3rd party solution there are many such people around, but some are right cowboys so only use one thats trusted, and when entering ANY code, make sure you only do it ONCE, if it fails you only get 5 chances in total before the phone can only be unlocked via hardware only, so do not guess at these things.
Here is a trusted place, I help run the forum that owner has, and I have followed him for near 20 years now, and I've yet to see any complaint about him, I don't get a penny so don't think I'm suggesting them because I get something, I suggest them because I know the service is great, nothing more, but you can go anywhere you like, just make sure to check them out before parting with money, because there are many who will take the money and laugh if it goes wrong.
Now, I mentioned frequency's above, you need to know what frequency your phone will work on, and more importantly what frequency's are available where your planning to go, because there are several bands around the world, and not all are in every country, so if your phone wont work on the frequency of where your gong, unlocking it is a moot point, because it simply will not work, not unless they have a frequency that your phone will work on, as I say there are a few, the US uses a lot of CDMA and TDMA, the rest of the world mainly uses GSM, and even GSM has a few variations, eg 900, 950, 1800 etc, so we need to check this out before anything else.
Now not knowing your phone I've had to search for it's frequency range, but you will need to confirm this as I may of got a different model to yours (I saw a couple of variations), anyway this appears to be what your phone will work on:-
quad-band (GSM 850/900/1800/1900; GPRS/EDGE)
If this is correct you should be OK, but let me know where your going, and confirm if these are correct, then I can tell you for sure if it will work there.
