GNUsound is a multitrack sound editor for GNOME 1 and 2.
Online database that compares the performance of common sample rate converters.
WaveShop is a free, open-source audio editor for Windows XP/Vista/7/8 32-bit and 64-bit. WaveShop is fast, lightweight, and bit-perfect, meaning samples aren’t altered unless they need to be. Editing a portion of an audio file only affects that portion; the rest of the file is untouched. Blocks of audio can be cut and pasted without changing their contents at all. This is especially useful for patching a finished master without corrupting its dither. Waveshop’s features include peak, RMS and spectral analysis, normalizing, fading, sample rate conversion, audio generation, plug-ins, and more, all with unlimited undo and comprehensive help.