Well, for starters it's not the right forum. You're asking a Microsoft Excel question on an ArcGIS forum website.
Secondly, no one here is going to just write out an Excel compatible expression or macro to convert Lat/Lng to a projected coordinate system.
Lastly, since you ended up posting on an ArcGIS forum I have to ask, do you happen to have access to ArcGIS software. If so, the process to get what you want is not all that complicated.
