what about a Go compiler written in Go? is it bootstraped already?

It's being worked on for Go 1.4 (scheduled to release in December). It's the primary feature they want to get done for that release. There was a talk about in back in May[0]. rcs is working on c2go to convert the existing compiler to Go[1][2].

[0] http://www.confreaks.com/videos/3432-gophercon2014-go-from-c...

[1] https://code.google.com/p/rsc/source/list

[2] https://code.google.com/p/rsc/source/browse/#hg%2Fc2go

Go isn't bootstrapped, but there are parsers for go written in go in the stdlib. http://golang.org/pkg/go/ast/

They're working on it