If you are developer who is asked: how do we customize Great Plains – read this and you will have the clues on where to look further.

• Great Plains Dexterity – this is proprietary programming language and technology, designed back to earlier 1990th with the goal to build platform independent graphical accounting package – Great Plains Dynamics. Dexterity itself is written in C (following popular those days hope – that C will provide platform independence). You can install Dexterity from Great Plains 7.5 CD #2. Obviously it requires a lot of learning / training, but it allows your custom piece be seamlessly integrated with Great Plains interface. Nowadays, however – and this is a good thing – most of Great Plains installations are moved to SQL Server – so you can use Dexterity for custom forms drawing only and make the buttons run SQL stored procedures.
• Modifier with VBA. Unfortunately you have to purchase this tool and get new registration keys. If you are familiar with VBA customization for Access or Excel – you have all the skills needed – then you just attach your scripts to the buttons and fields on GP forms (you can modify these forms with Modifier – or just tough them with it).
• Continuum for VB/Delphi – we don’t recommend this tool, because it is using Great Plains as OLE server – and you probably don’t want to be trapped by old technology.
• Crystal Reports. Great Plains has its own ReportWriter, but
  
  
  its functionality is limited – you can’t do cross modules reports (you can’t link Sales and Purchasing tables in one report, for example). So – you use Crystal. The GP tables structure is in Tools->Resource Description->Tables … and you are in control. Feel free to create views and stored procs directly in the companies databases – it doesn’t hurt the Dexterity engine
• Direct web publishing from Great Plains SQL databases, using Visual Studio.net and your language of choice (VB.Net, C#, J#, etc). Plus you probably want to have several SQL stored procs.
• eConnect – this tool is type of SDK with VB.net samples. It allows you to feed data into Great Plains and was primarily created for eCommerce developers.
• Integration Manager – it is end-user tool for importing to GP, however if end-user meets some challenges in the integration – you as a developer can help with VBA scripts. IM validates 100% of business logic and uses hidden GP forms – so it maybe slow for big on-going integrations, when you have thousands records per day – in this case you rescue to eConnect or directly to SQL store procedures.
• SQL queries - as a developer you have unlimited potential in using SQL queries, because the database in MS SQL Server.  Be careful, it is kind of surgery - you can easily delete all your customers, by executing: DELETE RM00101

ABOUT THE AUTHOR
Andrew Karasev is Chief Technology Officer in Alba Spectrum Technologies – USA nationwide Great Plains, Microsoft CRM customization company, serving clients in Chicago, California, Arizona, Texas, Florida, Georgia, New York and having locations in multiple states and internationally ( http://www.albaspectrum.com ), he is Dexterity, SQL, C#.Net, Crystal Reports and Microsoft CRM SDK developer.