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.
solder solider soldier soldiery slider sledder solidary salter slater saltier slotter slitter saluter slatier siltier sleetier slittier sluttier solitary zoolater solitaire sultry saltire salutary zoolatry
alder holder balder melder golder bowlder molder boulder gilder folder aulder wielder moulder shielder yielder wilder colder shoulder older guilder milder solder welder polder fielder elder gelder bolder builder ladder gladier collider moulter bladder kelter coulter blader lauder jolter palter tilter poulter solider soldier bleeder quilter alter welter weldor melter lewder wieldier shelter jilter bloodier leader cloddier loader belter clowder louder sledder molter gladder welldoer cloudier halter pleader bouldery lader balladeer philter colter mouldier kilter plodder milter colluder vaulter lieder falter caldera moldier flooder filter killdeer slider glider salter bladdery leadier eluder bolter realter reloader coleader deluder pelter
sold soldo soldi solid isolate souled solute soloed solidi solate soled soiled slide slid sled sild isolead