You can use "Update Inventory" dialog to update your products pricing or quantity in stock.
Format of file for updating inventory:
Where the first column is product SKU (productcode). The second column is price or quantity of a product depending on your choice in update inventory dialog.
Note for Macintosh users: On Mac new line symbol is different from the new line symbol in Windows and UNIX (Mac - 0xD Windows 0xD 0xA, UNIX - 0xA). Import script can accept only Windows and UNIX newline symbols (only first line will be imported from Mac files). Possible solutions:
1. Prepare your excel file on Mac then copy xls file to PC and save as CSV file.
2. Use one of the Mac to PC text conversion utilities freely available on the net.