rkk01 – Why not get back in touch with them?
We did exactly the same (we were the couple without kids); we just couldn't be bothered with all the talk of babies, nappies, puke etc. We'd rather have been in a nice restaurant/at the cinema/on the razz etc.
However, when we finally did have kids, our friends brought us back into the fold. Don't get me wrong, we hadn't detached ourselves completely, but only saw them once a year or so.
Now, we're closer than ever and see them loads – even with the 150mile distance. Or two (aged 2.5 and almost 4) absolutely love their boys to bits – and it's reciprocated. Their boys are aged 10 and 12.
If you really value their friendship, give them a call – I'm sure they'd be grateful and will find your experience with your growing kids invaluable.