I have used both iLink and the IRLP systems.
'iLink' is just getting a remote connection to a radio. This radio can be someone's 2 meter radio tuned to a local repeater, or a direct input to the repeater, or a 10meter radio etc... consider it a remote base connection.
It is fun to have access to a multitude of radios in all parts of the world without having to go there to operate, but be more careful about operating rules also.
You are operating someone elses station which holds the license for this activity.
There is also the chance to have an internet only based chat with other hams. This feature is useful but it is not using a radio for any part of the communication.
Have fun and do try to get the latest software. Start here: http://www.aacnet.net/