[Gdal-dev] Newbie needs help with RGB images

[opcode at telus.net]

I'm just getting started with GDAL in my code( 1 day under my belt :-) ) and 
am looking for some direction on how to load a GeoTiff (or other ) image and 
convert it to a RGB image buffer. The tiff image is 20,000 x 24000 x 3 and I 
want to downsample it into a 1024 x 1024 x 3 RGB image. 

I am thinking I can get it one band at a time with the dataset->RasterIO 
method and changing the offset each pass but this is likely to be very slow as 
it will downsample the entire image for each band. Is there any way to 
directly create the interleaved RGB?

Thanks
Frank