actually, yes: the Linear Frame Buffer is one contiguous memory area that maps your video memory. Unlike what happens with conventionnal SVGA (where you had only a 64KB window at 0xA0000.. 0xAFFFF) to access up to 4MB of VRAM, the LFB maps all your video ram, usually at high memory addresses.
What you have to do is call a VBE BIOS interrupt with the requested mode and one bit of the mode says "Enable VBE please", which should be 0x4000, but i'm unsure, so better check it
Once this is done, the BIOS will return you the physical address of the LFB, which you usually cannot use in real mode (for it is beyond your address space), but that you can nicely access or map through paging once in protected mode (unreal mode can access it too)
Hope it helps. Je peux le dire en Fran?ais, aussi, si ?a aide ;-p