Changing from Rogers to Fido Sim Card

Question

I called Rogers and they said try the internet...lol. I want to use my daughter's old samsung SGH-D807 as my cell phone but my provider is Fido and apparently it isn't compatible. Can I make it compatible as I like her phone a lot better? I hate to throw it out and I'm not switching to Rogers just to use the phone.

I have a Virgin Mobile Samsung r610 that was switched to an MTS prepaid plan at the MTS store when it was purchased. Through MTS I activated several features and they work fine (voicemail, call display,  etc.) but I cannot access the internet. How do I do this?