If you're writing a managed application, you can simply add
System.Drawing.dll to your references and then do this:

System::Drawing::Bitmap* bm = new System::Drawing::Bitmap("foo.tif");

The Bitmap object can then be drawn or its pixel data examined. See Bitmap's
MSDN entry for more information:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlr
fsystemdrawingbitmapclasstopic.asp

Note, however, that indexed formats are *not* supported. You would have to
first convert it to a non-indexed palette using a paint program or image
conversion tool. If you need to handle types of TIFFs that the .NET library
cannot handle, consider the LEADTOOLS Raster Imaging SDK, which supports
many additional kinds of TIFFs:

http://www.leadtools.com/SDK/Raster/Raster-Imaging.htm

Or the managed version:

http://www.leadtools.com/SDK/dotNET/RIP-for.NET.htm

If you're writing an unmanaged application, particularly if you must support
older versions of Windows, you might check out this project which uses
libtiff, a free TIFF library, to load a TIFF file into an MFC CBitmap:

http://www.codeproject.com/bitmap/BitmapsToTiffs.asp

I hope this helps.