It's at 16,960,000 shipped lifetime. More surprising is that it only did about 1.48m of that after DS launch, meaning a staggering 15,480,000 in just over 3 and a half years.
PSP will beat it, but only by virtue of being on shelves longer. After 3.5 years it had shipped only about half what GBA did in the same period.
The DS absolutely obliterated it though.
The GBA from launch until the launch of the DS was the fastest selling console in the world (ie a timespan of 3 years from launch)
Not quite beating the PS2 when you look at regions seperately, it beat the PS2 sales by ~3 million in America and 1 million in Japan, but Others the PS2 beat the GBA by 6 million (of course the PS2 staggered launch made little difference if you consider Sony couldn't make enough of them for anything other than a Japanese launch anyway)
(that shows how incredible DS sales were at launch in Japan)
(DS was not so incredible in Americas until later)