Preface: I don't know of an online tool for this, and I agree that the real solution is to practice IPA.
That said, there are a number of alternative phonetic alphabets (as James Grossman mentioned, though SAMPA is probably worse than IPA). Some of them might be easier to read: ARPAbet (http://en.wikipedia.org/wiki/Arpabet) is relatively approachable, for example. However, it still requires some learning to be able to read quickly.
You'd also need either a dictionary containing both transcriptions to search for words in (extant words only), or an IPA-to-ARPAbet converter; the latter is actually nontrivial because the phones in an IPA string aren't necessarily delimited, there's not an exact correspondence between most phonetic alphabets, and IPA may be used for either phonemic or phonetic transcriptions.
Googling, I found this Praat script which appears to contain an IPA-to-ARPAbet conversion function (http://students.washington.edu/riebold/files/Arpabet%20Vowel%20Analyzer.praat); and this Haskell file which seems to contain ARPAbet-to-IPA (http://rd.slavepianos.org/sw/sw-83/Sound/SC3/Lang/Data/CMUdict.hs).