Aliases are set by adding them to the name field of the object, in square brackets.
A complete list of Stargates and Stargate aliases can be found at http://opengate.ma8p.com/list.cgi
When dialing, a case insensitive match is done on the following:
Matches are done in the order shown. i.e. if there is a Stargate in the region named "Gamma" and there is also a Stargate with an alias of "Gamma", dialing Gamma will ALWAYS get you the Stargate in the region named Gamma.
If there are multiple matches at the same level then one of them is chosen at random. i.e. if there are two Stargates in the region Gamma, dialing Gamma will give you one or the other at random. However, to speed lookups, once a Stargate gets a match, it will remember that match until some other Stargate is dialed. i.e. the first dial to Gamma will be a random gate in Gamma, but subsequent dials from that same gate will go to the same destination in Gamma, until some other address is dialed.
Stargates may have multiple aliases. An alias appears in square brackets in the Stargate object name. i.e. If you name your object "OpenGate [prime] [my alias]" it's aliases will be "prime" and "my alias".
The special symbols used for Stargate addresses can also be used as part of an alias. Since SL does not allow special symbols in object names, escape sequences are required. The sequences \A through \Z, \0 through \9, and \. and \- are used to substitute for the special symbols.
As a shorthand, an alias beginning with a ~ is assumed to be all symbols, so the alias [\A\B\C] is the same as [~ABC].
Aliases with unicode characters can also be created by using u+XXXX to represent a unicode code point. For example, [u+661fu+9580] would be the Chinese Traditional alias for "Star Gate".
Note that while it is possible to set an alias with repeating symbols, the DHD cannot dial it. Also note that normal Stargate addresses are searched first, so an alias cannot be used to hijack another Stargate's address.
Please do not copy a gate, or rez multiple copies of gates, for the sole purpose of getting a specific gate address. The odds of getting a specific gate address by copying gates is about 1 in 20 million. It is futile. The best way to get your gate to respond to an old address is to use a special symbol alias, as described above.
A Stargate will never dial itself.