Access - Create unique ID combining letters and numbers

Hi,

Help! I have to show a group of school kids how to do this but I haven't used Access in years so don't know how to do it myself :s

For an Access project I need to be able to generate a unique student ID, which combines letters from the students name with a sequential number that is always one more than the highest currently in use. I have a forename field so I plan on using the first two letters of the forename plus a unique number. Is it possible to auto ID this?

Any advice would be appreciated.
Paul