When will Nikon replace the d3100 dslr?

I was just looking at buying either the canon 110d or most likely the Nikon d3100 and I was just wondering if/when they will replace it or upgrade it because its been out for a while now and I don't want to buy one then it immediately go out of date!

Nikon D3200 is on the shelves for quite a few months now
Canon have the EOD 550D, 600D, and now the 650D

And you are buying a DSLR right… Nothing in it to go out of date… Unless you need bragging rights
Any and any DSLR is good for life, unless it goes kaput
Period!

As the other answer mentioned, the successor already is available. I wouldn't bother chasing the latest model though. A DSLR is something that will serve you well for years to come, and it doesn't make sense to replace it every time a new model comes out. Therefore, when you buy your DSLR, you will likely use it for quite some time, most of which a successor model will be available.

I still used my D40 when the successor of its successor already was available, and it served me well. Meanwhile the successor of my D90 is available, but i don't see any need to upgrade to it. I'd even prefer my older prosumer grade D90 over the current up to date entry level lineup such as the D3200 or D5100

Several months ago.

Already has been replaced by the D3200, however this doesn't mean the D3100 is out of date. DSLR cameras should be considered as specialist tools, and thus require skill to operate because of this factor, it make the technology aspect less important. With all honestly a D90 (which is now five years old) is still a great camera because it's so good to use at the hands of an experienced photographer.

They already did! Look for the D3200. Haha!

So what if it goes out of date? Your pictures won't change. Picture quality depends mostly on your skill as a photographer. The camera, old or new, low-end or high-end, is only a tool.