Plenty of ICs
There are plenty of ICs around and with varying accuracy, I just checked Farnell at **broken link removed**
I found there also the LM335, altought with rather hefty price tag.
There are choices of analog output through to serial Digital and a duty cycle dependant temperature outputs. There are so many of them, it took me more than an hour to wade through it, but it was an interesting reading.
One good thing about these listings from Farnell is that you can "compare" all of them at an instant, then choose to look at these that suit you application the most.
RS Components would most certainly have an equivalent list.
Even if you do not want to order from them, it is a reasonably good overview of the chips available at the market in the present time.
Regards,
xanadunow