iTunes will automatically play songs without gaps, exactly as would happen if you play the CD. There used to a be user-configurable option to set tracks as "Part of a Gapless Album" - this is now set by iTunes. However, this setting never determined or affected whether there would be a gap or not between tracks - setting this (manually in older releases) does nothing unless you also have the Crossfade Songs option enabled in Edit > Preferences > Playback. When this is abled then iTunes will crossfade between songs unless:
- the songs are classified as being from a gapless album, and
- the songs are from the same album, and
- they are consecutive tracks.
the idea being that even if you have crossfading turned on, songs that segue into the next (like the tracks on Pink Floyd's "Dark Side of the Moon") will not be crossfaded.
There remains the issue of how iTunes now determines that an album is "gapless" or not, since this is now done automatically - using my own library as a test case and looking at the data that's serialized in the iTunes Library.xml file I seem to have, out of a total of approx. 4600 albums, exactly zero that do not have the "gapless album" flag set. Simple answer, though, is that you should be able to import the CD as normal and it'll play back in iTunes exactly as it does on a CD player.