17) SugarCRM
This popular open source alternative to Salesforce.com offers mobile versions that work on Android, iPhone, iPad and BlackBerry devices. Note that the native apps are only accessible with the paid versions of the application. Operating System: Windows, Linux, OS X, Android, iOS, BlackBerry.
18) vtiger CRM
19) openCRX
In addition to CRM capabilities, openCRX also includes groupware features that can be accessed from Android and iOS devices or PCs. It's Web-based, so you can access it from any browser, and it also synchronizes with Microsoft Exchange servers. Operating System: OS Independent.
20) Zarafa
Zarafa is primarily and open source collaboration and e-mail server, but it also offers a mobile device management plug-in that allows companies to remote-wipe lost devices. It runs on a Linux server, but provides e-mail that can be accessed from any browser or from BlackBerry devices. Operating System: Linux.
This app adds to the functionality of Android's Global Address List lookup. It connects with your corporate Exchange server. Operating System: Android.
22) K-9
K-9 is based on the e-mail client in Android, but adds some missing features. Those features include push IMAP support, attachment saving, BCC to self, signatures, flagging and more. Operating System: Android.
23) EGroupware
EGroupware is a messaging, calendar, contact, and to do list management server that can be accessed via the Web or any of the popular e-mail clients (including Microsoft Outlook). It also synchronizes with most smartphones via the ActiveSync protocol. Operating System: OS Independent.
24) Zimbra
This Microsoft Exchange alternative offers a mobile Web client that makes it easy to access e-mail, calendar and schedule data from the Web browser on any mobile phone. The mobile Web client is available in both the free open source version and the paid commercial version. Operating System: OS Independent.
25) Group-Office
In addition to e-mail and calendar, this cloud-based groupware adds basic CRM, file sharing and project management features. It also syncs with mobile devices, and it's available in commercially supported and hosted versions, as well as the free open source version. Operating System: OS Independent.
26) Simple Groupware
This app combines groupware features with content management functionality. Because it's standards-based, it integrates with most mobile phones, as well as Outlook. Operating System: Windows, Linux.
27) ERP5
In addition to ERP functionality, this app adds CRM, MRP, SCM, accounting, HR and PDM capabilities. It comes in a version for mobile phones, and it also available in commercially supported and SaaS versions. Operating System: Linux.
28) mBravo
The openBravo ERP software now has a mobile version for Android, and a demo is available on openBravo's forge site. Downloaded more than 2 million times, openBravo calls itself "the world’s leading web-based Open Source ERP solution." Operating System: Android.
29) Open ERP
OpenERP's CRM module syncs with your iPhone or Android smartphone, as well as Outlook. The ERP software also includes modules for accounting, point of sale, project management, warehouse management, human resources, and more. Operating System: Windows, Linux.
30) opentaps
Opentaps, which calls itself "the most advanced Open Source ERP + CRM solution," offers optional modules which make it available on mobile devices. In addition to the open source version, it also comes in paid professional and cloud-based versions. Operating System: Windows, Linux.
31) Connectbot
With this SSH client, you can connect securely to your corporate network to transfer files to your phone. Substantial documentation is available on the site. Operating System: Android.
32) iFreeBudget
This budgeting, accounting and expense tracking app also comes in an Android version. Its best for small businesses or home users. Operating System: Windows, Linux, Android.