Guild Roster Tools Info:

Use /grt to open the Guild Roster Export Tool in game.
GuildRosterTools will export to C:/Users/<yourcomputer>/AppData/Roaming/NCSOFT/Wildstar/AddonSaveData/<randomlookingletters>/<server name>/<character name>/GuildRosterTools_0_Char.XML

Guild Roster Tools will only auto-export regularly while you are logged in, and this is triggered by events affecting your guild's roster (people logging in, logging out, opening the guild roster, etc.). You can manually override the auto export by opening using the slash command /guildtools and clicking the Export Roster button.

IMPORTANT: The data export client has been released, but if you're not comfortable installing and running command prompt commands with Administrator privileges, you may want to wait for the official "easy install" release.

If you don't want to use the installer, then you will find up-to-date xml data with a filepath similar to this one, where terms in < > are variables unique to your computer and game client: C:/Users/<your computer username>/AppData/Roaming/NCSOFT/Wildstar/AddonSaveData/<randomlookingletters>/<server name>/<character name>/GuildRosterTools_0_Char.XML

If you are running the export client:

You will have a .csv file created in C:\WildStar Rosters\ that contains your most current roster export. This file is created automatically by the client monitor service any time your addon save file is updated (when you reloadui, log out, or exit game). The files will be named in a way that you shouldn't have problems with overwriting accidentally by other characters (since your various characters might be in different guilds).

Other Required Libraries/Tools Info:

For those that are brave, smart, or fearless, here is the xml to csv conversion tool that we made to bring the data in. You can use the .csv with normal csv programs.

We are finalizing our code for a guild management template using GoogleDocs, and it will do everything for you except convert and upload your rosters. Pay attention to this space as we move forward to full release.

UPDATES: (newest listed first)

06/09/14:

Added a fix for the rare instances of reported errors of returning Circle members instead of Guild Members (as intended).

05/24/14:

Changed command to /grt to invoke the manual export window at the request of a user.
Changed the manual export information text to provide better information where to start looking for exported data.
Added raw data field for "Days Offline". This field is a decimal-based field, and is intended for use with spreadsheet programs to calculate offline times.
Added player level field as requested by a current user.
Fixed variable name that was causing an error.

05/08/14:

Removed library reference for methods no longer supported by Carbine.