Stephen Baxter's Phase Space. If those short stories, especially the ones with Reid Malenfant, grab you, then read the Manifold series. If you find yourself wishing it was more Alastair Reynolds, then the Xeelee Sequence.
There's also a short story by Stephen Baxter in Phase Space (a very excellent collection) called Dante Dreams where a researcher becomes aware of the dreaming consciousness of her own organelles.