What to use as a cover for dlsr during the rain?

I have a nikon d5000 and i'm wondering how much rain it can stand? Also i was wondering what i should use to cover it and the 300mm lens i will be using?

An umbrella.

A friend of mine just did a rain photo shoot. She put the camera on a tripod (when not in her hands) and taped an umbrella on the tripod. When it was in her hands, she put plastic wrap around it, (not on lens of course), and also had a friend follow her around while holding an umbrella over them. You may look a bit strange, but hey, it's all for the picture!

I wouldn't get it wet at all- try using a plastic bag or have someone hold an umbrella or a raincoat over it.

Optech makes such a cover. They are called rain sleeves.

The come in various sizes. The one I use covers my 300 mm f/2.8 lens and D3 easily

Vortex Storm Jacket.