Identify the Current Active Cell

I would like to highlight/shade a certain cell in whichever row I am currently working on. For example, whenever I am anywhere on row 10 I would like cell A10 to be highlighted or shaded a certain colour, and similarly for row 11 cell A11 etc. I have been looking for a function like ACTIVEROW or ACTIVECELL so that I can then use conditional formatting, but can't find anything.
I am using EXCEL 2007.

Please help. Thanks.

Thanks for that.
The only problem with this is that when moving to another row, all cells in the previous row are changed to no-fill.
Cheers.