network54
This is where all the technical Essbase experts hang out.  There are a few planning consultants that hang out there but the focus is mainly Essbase.  This site is not maintained by Hyperion in any fashion.

Hyperion Consultant blog A blog that I maintain that covers the pressing issues I run into while consulting on the hyperion product suite.  The topics range from technical steps involved in moving pag files to issues encountered in locating resources for a hyperion planning project.

Essbase Blog by TimF Tim has been a staple on network54.  He's started writing a blog about specific technical issues encountered when administering the essbase product.  This is technical stuff you can touch.

Tim Tows Hyperion Blog Tim is a foremost expert in terms of programming the essbase api via c, java, or vb.  He has a couple of intereting products that his company, AppliedOlap, sells that allow you to greatly extend the functionality of the essbase product. Web deployed spreadsheets against essbase, he's got a product for that.  I need to setup a time to learn about his new product, Dodeca.  It sounds like he's come up with a great tool that combines essbase and relational in the same reporting / budgeting interface.  Frankly, this is something that hyperion planning is still overlooking.

Essbase tech support
877-901-4975, you just need to know your companies authorized Hyperion contact and license key and you need to have a little patience.  The ability of of the current support team to understand issues had diminished greatly.  There are still some really good 2nd tier support folks but it can take some time to get a good one.  Tier 1 is a little more painful to deal with than it used to be.

Application manager or Administration Services: Help menu option
Hyperion has done a nice job of building into the help facility all possible commands.  You get options for Functions, calculation commands, Report writer commands, Maxl statements, and finally Esscmd commands.  Each selection will bring up a definition, description, and finally an example of the command.
 

www.cubegeek.com  A multi faceted olap informational web site.  Most users appear to have an Essbase background.

http://cobb.typepad.com/cubegeek/  He's changed the location of his blog but this blog represents a good high level view of one persons view of where Hyperion is going.  Michael provides a good view of where Hyperion is going.  One thing that adds to his perspective is that he spent some time with Hyperion in the capacity of senior solutions consultant. 

www.essbase.com
This site is owned by Hyperion.  There are question and answer areas for all facets of Essbase broken into the following categories:
Server Operating systems, Administration, Server Calculation Engine, Front-End tools/ Clients, Languages/Developer Connection, OLAP Data sourcing, and Misc.  The misc section is where job seekers and posters converge.  Some "free ware" tools that people have developed for Essbase are also available here.

www.olapunderground.com - gone.
Now  defunct site.  This is a site that previously developed "free" utilities for Essbase.  Mainly tools that make administration of Essbase a little less painful.  One of their more useful products is the outline extractor.  Be sure you test any programs on a test server before running them on your production database.  This software was last updated for Essbase 6.5.  The outline extractor has been turned into an open source project sponsored by Tim Tow at AppliedOlap.com.  It's located at the following section of Tim's website: Outline Extractor The best part is that Tim has taken care of recompiling it for every version of essbase in existence.

www.essspace.com A new Essbase message board.  They are making changes based on feedback.  This is a supplemental to the network54 group because there are apparently 3 moderators that have worked with Essbase.  They've written a couple of utilities that can be downloaded without registering who you are (nice).