ProxyWay - Find proxy servers for OGame
I wrote about using proxy servers to hide your multiaccounts before, but here's a tool that will make the process of finding fast and reliable proxy servers much easier.
ProxyWay provides anonymous surfing and allows you to hide/change IP address from the web sites you visit. You can easily configure different browsers/applications to work through ProxyWay, it doesn't matter if you like Firefox or some other browser, the configuration is simple. You can even play OGame in a browser, while in the same time some bot does all the work on a different account. I won't get much into details about how to set it up here, since there's an awesome guide on ProxyWay website.
ProxyWay can also make your multiple OGame accounts even harder to detect by GO's since it can filter out proxy servers by country, so it can actually seem like you're playing from the same country - but you have a different IP.
There's a free version of ProxyWay; it may not be the best or the prettiest software out there, but it does it's job.
(Thanks to James for the tip!)