According to Nokia Canada the 3555 is a quadband phone. If it's unlocked it will work in Europe with local SIMs.

To determine if your phone is unlocked you need to try a non-Rogers/SO/PCM SIM, e.g. a Fido SIM (or any foreign SIM.) If using that SIM you can connect to a Canadian network then the phone is unlocked.

However, it will work with a Rogers SIM.

Because PCM and SO operate on Rogers' network.

Does anyone know how/where I can get it unlock so that I can put in a new SIM when I travel to Asia?

Links to several unlocking sites have been posted on this forum, e.g. here. These sites charge money for their service. I have no persona experience with any of them.

If you want to gamble, wait until you get to Asia, then when you go to a local cellphone store to get a SIM, ask them to unlock your phone. Another option is to buy a local phone/SIM/airtime package in Asia. Sometimes that's cheaper than paying to get your own phone unlocked.