Update README on how to send proper patches

Add a few lines of explanations on how to correctly setup
and use Mercurial to send proper patches.

README

@@ -45,6 +45,35 @@ Patches should come with the appropriate SoB line. A SoB line is typically
 The SoB line is clearly described in Documentation/SubmittingPatches , section
 12, of your favourite Linux kernel source tree.
 
+Then you'll need to correctly configure Mercurial. There are two extensions
+that you may find usefull:
+  - mq        : http://mercurial.selenic.com/wiki/MqExtension
+  - patchbomb : http://mercurial.selenic.com/wiki/PatchbombExtension
+
+Here's a typical hacking session:
+  hg clone http://ymorin.is-a-geek.org/hg/crosstool-ng crosstool-ng
+  cd crosstool-ng
+  hg qinit
+  hg qnew -D -U -e my_first_patch
+  *edit patch description*
+  *hack* *hack* *check* *fails* *hack* *hack* *check* *works*
+  hg qref -D -e
+  *edit patch description, serving as commit message*
+  hg qnew -D -U -e my_second_patch
+  *edit patch description*
+  *hack* *hack* *check* *fails* *hack* *hack* *check* *works*
+  hg qref -D -e
+  *edit patch description, serving as commit message*
+  hg email --outgoing --intro   \
+           --from '"Your Full NAME" <your.email (at) your.domain>'   \
+           --to '"Yann E. MORIN" <yann.morin.1998 (at) anciens.enib.fr>'    \
+           --cc 'crossgcc (at) sourceware.org'
+  *edit introductory message*
+  *wait for feedback*
+  *re-send if no answer for a few days*
+
+Note: replace' (at) ' above with a plain '@'.
+
 CREDITS /
 _______/