This should get you started. It loops through each member of each group.

Using oAccountinfoR As AccountInfoReader = Account.EnumGroups(oLFSession)
    For Each oAccountInfo As AccountInfo In oAccountinfoR
        Select Case oAccountInfo.TrusteeType
            Case = TrusteeType.LaserficheGroup
            Case = TrusteeType.LaserficheUser
            Case = TrusteeType.WindowsAccount
            Case = TrusteeType.LfdsAccount
            Case = TrusteeType.LdapAccount
            Case Else
        End Select
    Next
End Using

If you have the account name or account ID or acocunt SID then you can do something like this:

dim oAccountInfo As AccountInfo =Account.GetInfo(strAccountName, oSession)

Hope that helps.

-Ben