Project Management
Not too long ago we used a combination of an internal job tracking system, a white board (non-virtual), and excel to manage our projects. As we've grown those systems didn't scale. DotProject is an open source project and task management system. We use this system day in and day out. It is how we coordinate all our developers, projects, tasks, billing, client documents, schedules, pipeline and contact information. We decided on DotProject because we can customize it to our particular needs. We host our own implementation since it's so critical to us. However, there are companies that specialize in hosting and customizing DotProject--Big Blue Hat is a specialist in DotProject implementations.
Another popular project management web app is Basecamp by 37Signals. It's most popular among smaller companies. 37Signals has other products as well, for CRM, collaboration, and calendars.
CRM
When I last wrote about Internet applications we were using SalesForce.com for Customer Relationship Management (CRM). SalesForce is still a leader in the online CRM world, but we've found that DotProject, while not a CRM, covered almost all the ground that SalesForce did--at least for how we were using it. We found that DotProject, with a few tweaks and bends, performed both functions for us. SalesForce is still a great provider for online CRM.
SugarCRM though, is similar to SalesForce. It's built upon the open source DotProject system. We looked into SugarCRM but in the end we decided that a pure project management system, altered to perform our lighter CRM needs, worked better than a CRM did for our project management needs.
Zoho has a CRM solution as does Etelos and 37Signals.
For other CRM solutions try Salesboom.com
Check out Commence CRM which is 100% web-based and runs on Windows/Mac/Linux.
You can try web based CRM free for 3 users.