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.
sperm spirem spireme supreme supremo sapremia sapraemia
perm sperm deperm pram prim prom cuprum
spar spare asper super spurrey spry sparrow sparry spear speer speir spier spiraea spire spirea spiry spore spray spree sprue spur spurry supra osprey