Are there any release dates for Dx10 cards?

Are there any release dates for Dx10 cards? How about games being developed with Dx10 requirements? Just wanted to know how much life span I will have if I bought a new high end card.

DirectX 10 cards are dependant on when Windows Vista is realsed, since WV is the only OS that can support DX10. We are likely to see another generation of DX 9 cards before we start seeing DX 10 cards.
Not quite. DX10 is coming out with Vista, but the cards could come out earlier. Some rumours say that DX10 cards will come out this Fall, I do think they'll come out next Spring after Vista. Nothing official yet.

I'm interested in knowing too although, from previous experience, it may be worthwhile skipping the first generation of DX10 cards anyway.

While it's true you wouldn't be able to access DX10 features until tou have Vista (some people are running Vist betas), they could release fully featured DX10 cards now so you wouldn't need to upgrade later. Then again, cards progress so fast that that would be more than likely pointless.

As to why the cards might be released early? Well Vista has been delayed a fair amount, but the hardware probably hasn't so it may well be ready as per the original schedule. Then (mostly) ATI and nVIDIA have to decide whether to old the cards back (and make money out of the current range) or move on and take advantage of a range that might otherwise become obsolete before Vista is with us.