README: add installation info

README.md

@@ -1,10 +1,20 @@
 ## id3chap
 
 A command-line tool for adding ID3 chapters to an MP3 file.
+Most of the grunt work is done by
+[my fork](https://github.com/jcs/id3-go)
+of the `id3-go` Go library.
+
+### Installation
+
+    go get github.com/jcs/id3chap
+
+This will fetch, compile, and install an `id3chap` binary as `~/go/bin/id3chap` (or
+wherever your `$GOPATH` is).
 
 ### Usage
 
-    id3chap file.mp3 0 "chapter 1" 123 "chapter 2" 456 "chapter 3"
+    id3chap file.mp3 0 "chapter 1 is great" 123 "chapter 2 is ok" 456 "chapter 3 is boring"
 
 The first argument is the path to the MP3 file, then pairs of arguments each containing
 a start time in seconds, and the chapter title.