Hi Cem,
I too agree with Ankit for Cell Tooltip, but if you want to display say alv when it mouseover at some field then you can try the below mentioned procedure.
You can check the sy-ucomm as '&IC1', then after followed by the Check if the same field is what you want to provide information for and if it is success then you can proceed with further action.
Please validate this at your end as well, let me know in case you need any further inputs from my end.
BR/Thanks
Pranav Agrawal