If I recall well, you submitted your web-site at the yahoo! directory, so it's rather normal that Yahoo! spidered your web-site quite deeply.
Looking at the yahoo! listing
we already find you newly http 301 redirected URL such as this page
and others with still the old www.newindianmodels.com/forum/post-55.html
which will soon disappear as they are http 301 redirected
So I guess this situation is just not new, Yahoo! did have a longer list, most likely because it first was.
Google and MSN did not, so far, have a good path to your new forum (remember the forum link thing ?) so they did not spider it well yet.
If you look at the Google listing
you can see the few link that where already in cache where properly http 301 redirected to your new urls.
It's just that Google must be now massively crawling your newly installed Google sitemap and thus your forum before it will start updating the cache.
don't worry, this take some time, but will work