update docs to tell how to get xs5.6sp2
diff --git a/tools/xen/README.md b/tools/xen/README.md
index c73f74d..3e28182 100644
--- a/tools/xen/README.md
+++ b/tools/xen/README.md
@@ -6,7 +6,10 @@
Step 1: Install Xenserver
------------------------
-Install XenServer 5.6 on a clean box.
+Install XenServer 5.6 on a clean box. You can get XenServer by signing
+up for an account on citrix.com, and then visiting:
+https://www.citrix.com/English/ss/downloads/details.asp?downloadId=2311504&productId=683148
+
Here are some sample Xenserver network settings for when you are just
getting started (I use settings like this with a lappy + cheap wifi router):