Once you enable the Developer Dashboard in SharePoint 2010. See below for instructions by Jie Li using Powershell or STSADM:

  1. STSADM: stsadm -o setproperty -pn developer-dashboard -pv OnDemand

  2. Windows PowerShell:

    $svc=[Microsoft.SharePoint.Administration.SPWebService]::ContentService

    $ddsetting=$svc.DeveloperDashboardSettings

    $ddsetting.DisplayLevel=[Microsoft.SharePoint.Administration.SPDeveloperDashboardLevel]::OnDemand

    $ddsetting.Update()

You can write log information out to the Developer Dashboard using  SPMonitoredScope see more details here: http://www.wictorwilen.se/Post/Improve-your-SharePoint-2010-applications-with-monitoring-using-SPMonitoredScope.aspx?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+WictorWilen+(Wictor+Wil%C3%A9n)

This certainly is quite different from writing to the ULS logs in MOSS / WSS using TraceProvider.