Webtel
Usability: 
www.webtel.mobi (xhtml-mp)
Webtel.mobi offers low cost international calling and texts. For calls, webtel uses a callback system similar to competitors Rebtel and JaJah. You enter the party you're calling's number on the the mobile site and webtel calls you back with the call connected. Calling rates start at 3 cents/minute (plus a 5 cent connection fee). Rates vary among the three services depending on the country pairs involved so you might want to do a little comparison shopping before you pick one. webtel does have the advantage of covering calls between 240 countries which is considerably more than JaJah and RebTel. You can find each service's rates on their desktop sites:
Texting with webtel works similarly to calling, you enter the number and message into a form on the mobile site and webtel sends the text. The SMS's "from" field has your mobile number in it so replies will go directly to your phone. Texting rates start at 3.5 cents per message.
Credit can be purchased in € 5 increments. It's not clear from the webtel site if credit expires and if so how soon. This could be an important consideration for light users.
