I need to enter an entry from one workbook to another and also update the entry when I put new information in it. e.g I have one main soure file inventory.xls and I have few other files with lot of worskheets(tabs). What I need to do is if I enter an entry in worksheet if should enter that entry into the source workbook i.e. inventory.xls

Please help

Open the sheet with the data you want to reference. Copy the cell (or range). Then open the workbook you want to display the values in. Select the cell you want to display it in, then use Paste Special. Then select Paste Link.

Scott is correct, that's the fastest, simplest way to create the cross-references.

Once you've created that cross-link, you won't have to have the first document open at all for it to work, when you open the second document (by itself) with the cross links in it, you will receive a new message "This workbook contains links to other data sources." Be sure you select the option to UPDATE links so data displayed will always be correct. (see pic 1)

Lastly, this cross-referencing requires your documents to be in the same place on your hard drive that it was when you made the links. If you move the docs to new folders or new computers, you will have to update the links when the error message pops up (see pics 2 & 3).