This post I am putting togather steps to create a new Itinerary using ESB in BizTalk 2010. I am assuming people are familiar with BizTalk 2010 and have installed ESB toolkit 2.1. If not get it from here.
Once it is installed configure it using EsbConfigurationTool. You can find it at "C:\Program Files (x86)\Microsoft BizTalk ESB Toolkit 2.1\bin\EsbConfigurationTool.exe" on your local machine.
After configuration run "Install Itinerary designer extension" from Microsoft ESB toolkit 2.1. This will install a plugin to Visual Studio which you can use to create ESB Itinerary.
Open Visual Studio and open new BizTalk ESB Itinerary Designer project.

I have named it as TestItineraries. Double click to open TestItineraries.itinerary. This is blank page. Drag and drop On-Ramp, Itinerary Service and Off-Ramp on page.
Now before configuring anything go to BizTalk administrator console. Create a new application TestItineraries. Create a receive port and and receive location:
Receive Port - TestRP
Receive Location - TestRL1
Type - File
Receive Pipeline - ItinerarySelectReceivePassthrough (We will configure this later)
URI - local directory
Create a dynamic send port:
Send Port - TestSP1
Send Pipeline - ItinerarySendPassthrough (We will configure this later)
Go to filter of Send Port and configure it as below. You will need to add reference of application where BizTalk ESB is deployed.

NOTE: Unless this filter is configured i.e. all the values as shown, itinerary will not be saved.
Now come back to designer in VS.Click on OnRamp1. Go to properties. Select properties as shown in diagram below:

Select BizTalk application and receive port from drop down in properties.
Select OffRamp1 and its properties. Select from dropdown of Extender - Off Ramp Extender. Select BizTalk Application and Send Port. It will look like below.

NOTE : See Service name, state and type is auto populated from filter of send port.
Now lets go to the Itinerary Service 1. Select it and go to properties. Go to Itinerary service extender. Select off ramp extender from dropdown. After this go to Off Ramp and select Off ramp 1 and send handlers. It will look like :

Click on Resolver of ItinieraryService1. Right click and add new resolver Resolver1. Select properties of Resolver 1. Select Static Resolver Extension from Resolver Implementation. Set Transport location to local directory and TransportName to File.

Select the connector from Toolbox and connect OnRamp1 to ItineraryService1 and ItineraryService1 to OffRamp1.

This completes part 1.