Can I use my oven for sous-vide

Accuracy of the temperature is going to vary by oven, so there's no definitive answer there. As GdD said, you'll just have to get a thermometer and try it.

However, I think this will probably work fine for most sous vide applications. While sous vide is all about precision, a couple of degrees fluctuation isn't going to make a huge difference for most preparations (eggs are a notable exception), particularly given the thermal mass of the water. You could also throw a pizza stone or something in the oven too to help keep a more constant temp.

As for accuracy that's not something this forum can say. If the oven is accurate and the temperature does not fluctuate more than a few degrees then yes it would be accurate enough, but if the fluctuations are more then no. The only way to find out is to get a very accurate oven thermometer and test it.

Sous vide cooking requires water to be flowing around the food which is why sous vide machines have a water pump to keep the heat evenly distributed. In an oven pot you'd likely got hot spots and cold spots as there won't be any circulation besides convection, which may not be enough. Without some sort of pump you'd probably get uneven cooking.

Of course you can use your oven for cooking sous-vide, though you will not get very precise temperature control and will pay a higher electricity bill than if you use a water bath. I would not use it for long cooking periods at a limit temperature where safety can be jeopardized (around 55ºC) or when high precision is required (e.g. eggs), but otherwise it's perfectly doable.

You must play with your oven model until you find the best settings, usually 10 or 20 degrees C higher than the desired water temperature. Using a heavy pot such as a dutch oven will also help to maintain the temperature.

The technique is analyzed in detail here: http://sousvide.wikia.com/wiki/Give_Sous-vide_a_try_without_buying_expensive_equipment

Oven thermostats are very inaccurate, and by design allow very large temparature swings. A heavy pot full of water is a pretty good buffer ... it will even out the temp a bit.

There are precision ovens designed for this, called c-vap and combi ovens. They are expensive and power-hungry and complex. Even these have issues with precision. They are more than good enough for low-temperature cooking a roast, but the imperfect temperature stability causes problems for small things.

I believe the answer is you can't use your oven like a sous vide because the physics are very different. Air is a terrible medium for heat transfer while water is one of the best. This is what makes sous vide work.