SMac:
I read one where he was a statue placed in the garden at the Hyperion where Buffy was staying. It was post-Chosen canon fic. He was conscious within the statue also. I think it was the same fic where a little boy Spike is growing up there also. That's all I remember except that it was well done and no I don't recall the name.
Now this is going to bug me... Is it the same story or are there two conscius Spike in a statue stories out there...???
In the fic you're referring to, it's Buffy that's a statue in the gardens. She was turned into a statue by the Immortal and sent to Angel. Spike has come back as a human baby, after he dies in Sunnydale, and Angel is raising him as his son...good read, very long and angsty.
I believe it's already been asked about and found here, check the 'found' section.