Register to use D-Star
Do you need to register for D-Star, the answer here is not quite as clear cut as it once was, in order to use Icom G2 or Icom G3 systems, yes you need to have your callsign registered with the Icom network. How do you know if the system you are using is part of the Icom network, or some other thing - well that isn't so easy. In general reflectors that you can connect to with the "REF" name are more likly to be Icom based, but not always (since XLX reflectors also work using the DPlus "REF" protocol).
To say that this isn't exactly clear for users to understand, is an understatement for sure, so best course of action is to get registered and that way you have your options covered.
How do you register? Thankfully that is quite simple. For UK based users, you can register directly with Icom UK, you can follow the instructions here: https://icomuk.co.uk/News_Article/2/1052/.
Anyone with a valid callsign can register here: https://regist.dstargateway.org/Dstar.do, simply click the "Register" button in the middle of the page.
A quick video quide to using this system to register can be found at the following location: https://regist.dstargateway.org/Dstar.do.
If you would like to check your D-Star registration status, please do so in the "D-Star Tools" section of this website, here is a direct link: http://www.pistar.uk/d-star_regcheck.php.
Note: Some D-Star reflectors have required a CCS7 (DMR ID) in the past, even if you only use D-Star, you may also need a DMR ID registered, see the DMR registration instructions available here: http://www.pistar.uk/new_dmr.php.