There are multiple ways to build an integration with ServiceNow.
Depending on your company needs, budget, and timeframe, there is an integration that can meet your needs. Check out these possible integration methods below.
Note: This article is a supplement to the ServiceNow Wiki article on integrations:http://wiki.servicenow.com/index.php?title=Integration_Overview
ServiceNow provides plugins that integrate ServiceNow with other programs. These plugins often use webservices as part of the plugin, or vendor specific probes. Plugins can require some configuration to meet your needs, but are a helpful start to building your integration.
You can use Webservices to transfer data between programs. This is a preferred integration method, however it can be dependent on your company knowledge of webservices.
Connect to ServiceNow with soapUI to test different SOAP requests http://www.soapui.org/
You don't really need to understand webservices completely to utilize them in ServiceNow. ServiceNow makes them easier to use. However, understanding the basics of webservices is helpful.
Note: You can build a ServiceNow integration with Webservices without a ServiceNow plugin.
A CSV or XML can be placed on the Midserver or FTP server to import into ServiceNow. You can schedule the import of the XML/CSV file and ServiceNow imports it using an import set and transform map.
Note: You can build a ServiceNow integration with XML/CSV without a ServiceNow plugin.
You can use JDBC to connect to other databases through the ServiceNow midserver. This is through a scheduled job or script.
Note: You can build a ServiceNow integration with JDBC without a ServiceNow plugin.
You can create Inbound and Outbound Emails to/from ServiceNow to transfer data. This method can have issues with reliability, but sometimes it is the most cost-effective solution.
You can access ServiceNow through URL both to query data and even create data. There are may possible integrations that can be done this way. You may have issues with cross-site scripting violations, but I have seen some elaborate integrations built this way. I prefer webservices of course, but it I think these integrations are interesting that they can accomplish so much just by using url.
SSO and LDAP
You can build an integration using various methods for SSO Authentication.
You can access readonly ServiceNow through ODBC. You can build reports using external reporting tools like SAP Business Objects or Cognos using a ODBC connection. You can also use ODBC as integration if you are just creating a one-way data flow to other applications.
There are also other methods to build a ServiceNow integration. However, I hope this gives you some ideas and gets you started.