Don't know if you've come accross this excellent site before. It has thousands of species calls listed and sonograms of most of them. You can register and upload your own recordings.
Here is a sonogram of a Water Rail that I recorded on my Remembird device (http://www.remembird.com) this afternoon at the old reservoir on the Great Orme. It was first heard this morning and was still present late afternoon, only the second known live record (one was also found dead many years ago). The sonogram has been created using Raven Lite 1.0 (Raven Lite web-site), a free interactive sound analysis software available on-line and really easy to use.
Other birds seen this morning included a fine Lapland Bunting in off the sea (found by Paul Leafe), Merlin, calling Snow Bunting and 11 Long tailed Tit.