As Sven said vesafb isn't a module at 2.6.14. So for >=2.6.14 you need both,for <2.6.14 you only need to add fbcon to the conf file.
I'm sure you all spotted it - there is a slight error in the above statement, so for the record it should read:
"As Sven said vesafb isn't a module at 2.6.14. So for <2.6.14 you need both, for >=2.6.14 you only need to add fbcon to the conf file." It was about midnigth when I wrote that. Richard.