One can easily retrieve the MS CRM entities including the customized one using web services. For this the following web services needs to be referenced from visual studio .Net.

URL: http://<servername>:<portnumber>/MSCRMServices/2007/AD/CrmDiscoveryService.asmx?WSDL
Web Reference Name: CrmSdk.Discovery

URL: http://<servername>:<portnumber>/MSCRMServices/2007/CrmServiceWsdl.aspx
Web Reference Name: CrmSdk

Dim dt As New DataTable
       Dim dc1 As New DataColumn
       Dim dc2 As New DataColumn
       Dim dr As DataRow

       dc1.ColumnName = "Leads"
       dt.Columns.Add(dc1)

       dc2.ColumnName = "Oppertunities"
       dt.Columns.Add(dc2)

       Dim myCRM As New CrmSdk.CrmService
       myCRM.Url = GetOrgUrl()

myCRM.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials

       Dim myToken As New CrmSdk.CrmAuthenticationToken
       myToken.OrganizationName = "MindfireSolutions"
       myToken.AuthenticationType = 0
       myCRM.CrmAuthenticationTokenValue = myToken

       Dim colSetLead As New CrmSdk.ColumnSet
       Dim colSetOppertunities As New CrmSdk.ColumnSet

       colSetLead.Attributes = New String() {"leadid", "fullname"}
colSetOppertunities.Attributes = New String() {"opportunityid", "name"}

       Dim myQueryLead As New CrmSdk.QueryExpression
       Dim myQueryOppertunities As New CrmSdk.QueryExpression

       myQueryLead.EntityName = CrmSdk.EntityName.lead.ToString
       myQueryLead.ColumnSet = colSetLead

      myQueryOppertunities.EntityName = CrmSdk.EntityName.opportunity.ToString
       myQueryOppertunities.ColumnSet = colSetOppertunities

       Dim myAccount As CrmSdk.BusinessEntityCollection
       myAccount = myCRM.RetrieveMultiple(myQueryLead)

       Dim LeadName As CrmSdk.lead
       Dim OperName As CrmSdk.opportunity
       Dim dr1 As DataRow
       Dim dr2 As DataRow

       For Each myLeadEnt As CrmSdk.BusinessEntity In myAccount.BusinessEntities
           LeadName = CType(myLeadEnt, CrmSdk.lead)
           dr1 = dt.NewRow
           dr1(0) = LeadName.fullname
           dt.Rows.Add(dr1)
       Next


       Dim myEntOppertunities As CrmSdk.BusinessEntityCollection
       myEntOppertunities = myCRM.RetrieveMultiple(myQueryOppertunities)
       Dim iCntRow As Integer = 0

       For Each myConEnt As CrmSdk.BusinessEntity In myEntOppertunities.BusinessEntities
           OperName = CType(myConEnt, CrmSdk.opportunity)
           dt.Rows(iCntRow).Item(1) = OperName.name
           iCntRow = iCntRow + 1
       Next

       Me.GridView2.DataSource = dt
       Me.GridView2.DataBind()