Unlock codes are called "MEP" codes as well. You can try searching in Google for a
BlackBerry 8110 MEP2 code or you can try taking it to your local cell phone shop.
If you decide to purchase the code online, put "https:" infront of the website name. This will show you the site has what's called an "SSL" certificate on the site. This means that all credit card payments and paypal payments made off the site are secure. People who don't have that, they can actually take your credit card number. The SSL certificate will actually encrypt all of your information properly to protect you.
Credit card fraud is infamous online, so that's definitely something to check.