A sample working application built using Lift 2.4-M3 and scala 2.9.0-1 (works with scala 2.8.1 too) is deployed on github.
It has working example of LinkedIn API for profile search, people-search and company search with OAuth 1.0 authentication API implementation.
MongoProtoUser is modified to have more fields for user registration process. Forgot Password is modified to use AJAX.

It shows the following features of Lift to a new lift beginner-
1. Usage of lift-mongo-record for inserting and accessing mongodb documents. Query handling is done using Rogue library from Foursquare.
2. Usage of ProtoUser implementation as provided in Lift itself.
3. Apache POI is used for Excel generation from the mongodb data.
4. Scribe OAuth library is used for OAuth integration

How to start the application?
1. Clone repository from https://github.com/pawank/LinkedInAPI_Test
2. Go to the directory where git repository is cloned.
3. Create a new LinkedIn developer account if you don't have one
4. Change the LinkedIn developer API access key and secret key in src/main/scala/code/linkedin/LinkedInConnect.scala
5. Install mongodb and run the mongodb server using "mongod --dbpath /path/to/db/file"
6. Do "sbt update" to update all the dependencies. You may need to add few JARS locally which are found in lib/ folder.
7. Run "sbt ~jetty-run" to run Jetty at localhost:8080 port and see the application up and running
8. Create a new user by clicking on 'Join Us'
9. Use the credentials provided for the user to login into the application.
10. Click on LinkedIn link in the menu to perform LinkedIn authentication using your existing LinkedIn account
11. Perform API searches using the form shown on the localhost:8080/audience URL. Please note that it may have bugs but the idea is to show how to do LinkedIn integration