Photoshop- Placing a layer of text on an image bang in the centre

[DuncyBoy]

I've got some mobile wallpapers and want to put my name over the top with the transparent/negative effect reversing the colour behind. I can add the text layer no worries, but how do I centre the text/layer?

Here's one almost in the middle by hand:

 

[DuncyBoy]

Thanks for the replies, everyone

Seems there's plenty of different ways to do it- all of those are useful tools, thanks