I've got Medial Portal setup using 2 HDHR3's OTA grabbing the EPG with a program called MC2XML
http://mc2xml.hosterbox.net/ which goes out and grabs the same info that MCE uses. If you need more info on setting up the xmltv for MP follow the steps below
How would I use mc2xml with MediaPortal? *
Create a folder for the EPG data (example: c:\mc2xml) and put the mc2xml.exe binary and a copy of xmltv.dtd (
http://xmltv.cvs.sourceforge.net/viewvc/.../xmltv.dtd ) in that folder (use a GUI file manager or command line)
Optionally create an "mc2xml.chl" file listing the channels you want included in your EPG (see above for file format) (make sure that notepad doesn't append a ".txt" extension to this filename)
MediaPortal wants the produced .xml file to be called "tvguide.xml", so you must open a DOS box, change to the EPG data directory and specify the output filename on the mc2xml command line.
On the first run of mc2xml on Windows it will ask you to input your Postal/Zip code (ie: "10000"), Country Code (ie: "us"). If not using windows, you must specify this info on the command line.
mc2xml will then ask you to select a lineup number. mc2xml will save this selection to mc2xml.dat and create a tvguide.xml file in this folder. (Delete mc2xml.dat if you selected the wrong lineup, and try again)
md "C:\mc2xml"
cd "C:\mc2xml"
copy "C:\downloads\mc2xml.exe" "C:\mc2xml"
copy "C:\downloads\xmltv.dtd" "C:\mc2xml"
notepad "C:\mc2xml\mc2xml.chl"
mc2xml -c us -g (zip code) -o tvguide.xml
Start MediaPortal's "TVserver configuration"
Go to plugin "XmlTv" (make sure XmlTv plugin box is checked) and select the folder with the newly generated tvguide.xml (example: c:\mc2xml)
Go to Tab "Mappings"
Select your "Group"
Press "Load/Refresh"
The list box will now show your "channels" with drop down boxes to select the descriptions from the tvguide.xml file
After selecting descriptions, press "Save"
Verify the selections by pressing "Load/Refresh" again (all boxes should now be white)
Go back to the "Settings" tab and press "Import" (you should see your channels/programs after importing (takes a few seconds))
Close "TVserver configuration"
Optionally schedule a daily task to keep the tvguide.xml file up-to-date:
Start->Control Panel->Scheduled Tasks->Add Scheduled Task (Press Next)
Browse and Select C:\mc2xml\mc2xml.exe
Select daily -> Next
Set desired time -> Next
Set computer username/password -> Next
Check "Open Advanced Properties when I click finish", and click Finish, and set these options (modify paths if necessary):
Run: c:\mc2xml\mc2xml.exe -o "c:\mc2xml\tvguide.xml"
Start in: C:\mc2xml
Press OK