If you want to connect to the internet using a sim card, you will need to setup the internet connection settings on the Nokia n8, this is to configure the network provider's password, user name and access point. To get the correct internet settings that are for your network provider and for your Nokia n8, you can ring your network's customer service department and tell them to send you the internet settings. Once they place a request for the internet settings to be sent to your mobile phone, usually within 24 hours the internet settings will be sent to your Nokia n8.
Once the Nokia n8 has received the internet settings, make sure you save them by opening the message, select 'save' that is found in the 'options' and make sure the settings are automatically configured, it will ask you after you have saved the internet settings. Once you have done this, you will need to go into the web browser and make sure the internet settings are configured. To check if they are, select 'web', select 'options', select 'settings', select 'general' and finally select 'access point'. Below the access point heading, your network provider's internet settings should be listed, if not select 'options', select 'change' and find the internet settings that are for your network provider. Once you have found them, select them and select a website from the preloaded bookmarks stored in the Nokia n8 and test if the Nokia n8 can access the internet.