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.
gull gully gul gulley cull gall cully guile quoll quill gally golly quell cullay galley gal quillai gale glue glow glia quillaia kill gley gaol caul goal glee call gala colly galea kelly quail quale gaily galah calla gayly gluey
bull full hull cull gull lull mull null pull dull