Hi there, I have 7 year old identical boys, and I am an identical twin too.
Mine occasionally dress alike but choose their own clothes, they are best friends and share the same interests though their personalities are slightly different (1 leader, 1 follower, 1 gentle, 1 boisterous).
As an adult identical twin myself, I NEVER refer to them as 'the boys' or 'the twins' as it really hacked me off being called 'the girls' as we grew up. My sister and I are alike but share similar interests and extremely close, best friends. We still end up wearing very similar clothing even now but this isn't a problem its just funny when we turn up somewhere wearing virtually the same thing!
I give my boys space to discover their own likes and dislikes and I try to give them some of me apart from the other one.
I suppose my boys don't think there is anything at all odd about being the same as someone else, its a special thing, you always have your best friend with you! I never worried about the clothes thing until they were a little older, say 5. Chances are they would like to wear what the other does as they look cool.
We often share each others moods and find it unexplainable when suddenly sad until we phone and find out what the other is doing and have an explanation. She is the other half of me and I don't find it odd at all that we follow the same paths in certain aspects of our lives.
Our mother can't tell us apart on the phone so she simply says "Hello Darling" until she gets some more clues lol.
Sorry to ramble on and congratulations to all you twin parents.