Wait... How will you be handling the servers thing... like where I have a login...
If I understand your question correctly...
When the game supports it then it will ask you if you want to login when you first start (or when selecting multiplayer). This will contact mythruna.com and "log you in" from the game's perspective. When you connect to a game server, then you and the game server share some info and it also contacts mythruna.com to verify that it matches.
Then you select your character on that server and play.
The above requires a few game changes to happen so it won't be in effect right away. And the changes to support the server list will probably appear at the same time as well as the initial rudimentary character creation and selection screen.
and $5 is for all the version? if so I think you should raise the price tag...
$5 does not get you the game when it is released. It gets you an account and will get you $10 off the game. It's a way of contributing minimally even though you will still have to fork over a little money when the game comes out. If the game eventually sells for $15 then the $5 donator will still have to pay another $5... it works out to be the same as the user who donates $10.
I may raise the values of these donation levels when I eventually get closer to alpha to better align with the real prices. It won't affect anyone who has already donated since I'll just bump up their levels for them.