My "through youtube" didn't work. He also "attached" to the main account. Items like "Logoff", "change user", "add new" - are completely absent.
But in the "youtube REMOTE" - found everything you need.

Faced on the tablet ZT-180. (android 2.1)

It was not possible to add a second account to gmail. "Add account", the setup wizard starts, two buttons "Create", "Add". Click "Add ..." the refresh of the screen occurs and see the same two buttons (without any errors).
The solution through youtube did not work. He was already tied to the main account. The possibility of "change" or "add", did not find.
The "AddAccount" application did not help either: "Error: java.lang.SecurityException: caller uid 12345 is uid." The developer says "FIG knows what it means."

Now that HELPED! :)
Through the market put "Youtube remote". And in it, Menu / Switch Account / Add account, login / password - added (!). A couple of cries about "allow access to data." But in the list of accounts - did not appear (Youtube remote) :(,
I go to gmail / accounts - there is a new account (!). I choose it, again a couple of cries "Allow". "Click sync" - there is mail (!). Accounts switch :)
P.S. The standard add-on did not work, but this is not important anymore.

P.S.S How to switch accounts in google talk - did not find it. I would be grateful for the hint.