Technically Google plus is an upgrade - It requires an existing Google account - This can be a gmail accont (one example) or any other google account. Once you have one go to plus.google.com and then you will be prompted to upgrade to G+. As for the person saying to ignore Google, do you realise what you are saying? Ignore the SEARCH ENGINE WITH THE WORLDS LARGEST PERCENTAGE OF USERS? Not very smart - Remember this.... Google are now incorporating Google+ information right into search engine results - just like youtube videos - Thats just one reason why you should be using this service! there are many more.
Log into your Google Plus account then go to your profile. Look at the address bar and your Google ID is the long set of numbers after plus.google.com Let me know if you have any questions.
Google+ at the moment is in beta, and participation is by invitation only. As Alan says your Google+ ID will be the same as your Google one, but will not include the features of Google+ until you are invited, or they open it up to everyone.
Creating a google plus account is a very easy process , if one has user account in gmail , then he /she can directly switch on to google plus through gmail , if not then creating a new account in gmail is the only option.
If you have google e mail account then you can have google+ id very easily. Just visit https://plus.google.com/
one simple method to log in to Google+ in your PC just log in to the Google account.There you will find all of your accounts(Gmail,youtube Google+,orkut,etc) at the top left on the page the Google+ will appear as the "+you" then just by click on that you will automatically get log in if u have once log in before. For ur ID you click your picture at the topmost right on the page it will show the details of ur account.