I want to test my internet speed before playing online games but I don’t know how :/
and "there is an app for that" in the iTunes store
check out Speedtest.net, choose a server on the map and click on begin test, its should give you the speed in MBytes and Mbits
Speed Test and Ping Test
One of the most well-known site is speedtest.net. As Oron said, the result could vary depending on several factors, but it should give you rough numbers to work on. Choose the nearest server to your current location.
In this case, he should choose a server nearest the game server he will be using. It will give a much better indication of the performance he will see during gameplay.
Bruce is right. I missed the part about 'online games' and assumed that you just want to test your connection speed generally.
There are actually a number of "internet speeds". There are the raw download and upload speeds of your router/modem, which you can find out from the "connection" page when managing your router/modem. However, this tells you little about real life internet speed, since the local "pipe", to which your modem is connected, can be fast or slow, and it will be shared with other users. If you are connecting to a server which is on another continent or on a slow connection, you may find that the connection is slower yet.
In practice, I find that the simple answer for an all-around ball park figure is to use an online internet speed checker, but it needs to be in your country to have any meaning. Simply google "broadband speed test" and try two or three of the links and you'll get a good idea of your connection speed.