Gregor Gorjanc has a post on Excel and LaTeX that lists four ways to convert and Excel table into LaTeX. I’ve used two of the methods he lists: brute force and excel2latex. I recommend excel2latex. I used it frequently until I upgraded to Office 2007 and the plug-in quit working. The only bug I remember with it was that sometimes it would give you a warning saying it didn’t work, but it did; the LaTeX code you wanted was waiting for you on the Windows clipboard.
I plan to try out Gregor’s other two suggestions. Creating tables in Excel is far easier than doing so in LaTeX and I miss the functionality that excel2latex provided. Maybe there’s a way to use excel2latex with Excel 2007. If you know of a way, please leave a comment.