Multiple Access Database

at work we input alot of data into a single (very simple) Excel spreadsheet which is kept on a drive accessable by every computer in the office. The problem is once one person has opened it another cannot add or amend information because the file becomes "read only".

Is there a program which will allow more than 1 person at a time access and amend data in a simple database? i dont mind abandoning Excel if there is another program out there that can do what i need

MS Access comes to mind since it is easy to get with MS Office. There is also the openoffice.org database software. I'm not sure if is multi-user, it should be and best of all its free. I happen to use MS Visual Foxpro which may be too much for you.