There is no 64 bit Jet driver, so that means no Excel or Access support.
The OLE DB provider "Microsoft.Jet.OLEDB.4.0" has not been registered
There is no JIT for VSA scripts on 64 bit, so scripts must be compiled when developing the package (through the 32-bit designer tools). The PreCompile should be set to true, which is the default. The script is then compiled when the package is saved.
There is no Visual Studio support for Itanium (IA64) and therefore no BIDS, so packages need to be developed on another machine, but can then be deployed to and executed on IA64 machines. There is however full support for BIDS on x64 platforms.
When designing packages on a 64-bit machine, the default behaviour is to run in 64-bit mode. You may want to change this so that you can access 32-bit only resources, e.g. Jet. Within the Project Properties, select the Debugging page, and change the Run64BitRuntime property to false.
The default DTExec used will be the 64-bit version, but if you have elected to install the 32-bit runtime as well, you can use the 32-bit version of DTExec. This allows you to access 32-bit only resources such as Jet again. See C:\Program Files (x86)\Microsoft SQL Server\90\DTS\Binn\dtexec.exe
On a 64-bit version of SQL Server 2005, if you wish to schedule a package to execute a package under 32-bit mode, you will have to use the Operation System (CmdExec) job step type. The SSIS Package Execution step type will always use the 64-bit runtime, but by using an Operating system step you can explicitly specify that the 32-bit version of DTExec should be used. As above the 32-bit version can be found in C:\Program Files (x86)\Microsoft SQL Server\90\DTS\Binn\dtexec.exe.
Executing packages through SQL Server Management Studio (SSMS) on x64 or I64 machines will use a 32-bit execution host. So executing packages from within the object explorer may not be ideal.
DTExecUI.exe, the nice GUI sibling of DTExec is 32-bit only. To ensure you run as 64-bit just use DTExec.exe.
