Found this on google
www.aeroseek.com/webtrax/
Here you can follow flights by entering the flightnumber or departure and arrival airport. Yesterday I followed flight SLR 1841 to Punta Cana. my sister and her family was in it.
Now I have noticed that a lot of european flights are not in the database, but it's worth giving it a try. You can see on a map the position and in a table you see FL, GS , assigned Mach speed and ETA