I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
suppress suppers spires sprees spores sprues supers spares sapphires cypress spireas sappers sippers spurries spiraeas spurreys spurs spars superrace speers sparse spoors spears speirs sapors cypres sprays spiers sopors spruce sapours soapers zappers zippers sparrows spurious cyprus sprucy
press cypress oppress depress repress suppress guipures pores sprees pyres spires pries peeress preys koupreys prees apres peres pares prese pross spares priss spores presa sprues cypres