Once you have your google account, login here: Google docs or go to google’s main page in your browser. Go to More then Documents
After logging in, you can upload the ODT file to google using the Upload tab and select Files then go to the folder on your PC that your ODT file is located and select it. Click Open, you will then be asked to modify the upload settings. Just tick all of the boxes then click Start Upload.
Once you have the document in Google, you can modify the text to suit your needs. To save the document in the format of your choice (ODT, PDF, RTF, TEXT, MS WORD or HTML) goto File - Download As then select the format. EG: Word.
By the way, this is a great way to convert a document into a PDF file.
If you are frequently converting lots of documents, try using a converter program on your PC as the upload/download process can be tedious.