JohnW - 2:32 pm on Mar 31, 2012 (gmt 0)
It can hurt if you do wrong. How to change hosts without any Google probems is to make sure the changeover is fast and happens everywhere all at once in the eyes of G. So go to the new host and set the new nameservers to point to the current site on the old host. Set the TTL as low as allowed like 300 or 600. Then you can change the DNS to point to the new nameservers and wait a couple days. This way it doesn't matter if there is choppy DNS propagation since both sets of nameservers point to the same place anyhow. After 2 days and after everything is moved and ready, then change the new nameservers to point to the new location and put the TTL back like it was.
Don't forget to make sure everything on the site is identical. If you use the domain for mail pay attention to the mx records/accounts when you change the nameservers.