I have been working with Oracle 11g and SSIS on x64. The main issues I have seen are to make sure you have the 64bit Oracle Client installed on the server when running the packages on the server. In developing and testing you will have the 32bit installed on your workstation. If you are using script tasks then you will need to make sure that they are set to precompile and on the server you will need to open and close the scripts to get them compiled for x64. If you try to test and run the package in BIDS on the server then you will also need the 32bit Oracle Client installed.
You can also utilize the new connectors that were released for Oracle post RTM of SQL Server 2008 if you are interested.
For Oracle and Teradata, Attunity developed the components for Microsoft. Download from: http://www.microsoft.com/downloads/details.aspx?FamilyID=d9cb21fe-32e9-4d34-a381-6f9231d84f1e&displaylang=en
Hope this helps. If you want to provide more specifics in regards to the issues you are experiencing please post more and I will get back to you.