I have to develop an appliction (Asp.Net - maybe MVC) that would be integrated into SharePoint 3.0. This is the first time I have anything to do with SharePoint and I'd like to pick up the basics quickly. I haven't found any reasonable online resources - do you know any? Unfortunately, I don't have time to buy and read a book. Thanks.
When you say integrate do you mean simply have it available inside of sharepoint? If so then you don't need any books or tutorials it is very simple to embed your apps into sharepoint. We do this all of the time due to limitations within sharepoint. We write our ASP.net apps and use a web site web part that allows you to enter some basic information (such as the location of the web site) into the web part and then it is displayed right within sharepoint.
Creating and Deploying SharePoint Solution Files
SharePoint 2007 Deployment: Overview
Sharepoint is not a good development platform - This will give you a good idea of what to expect and what NOT to expect from SharePoint.
That's all I can think of for a start. If you have more specific questions I can direct you to different resources.