Skype SA, the Internet calling service that was controlled until last year by eBay Inc., filed Monday for a U.S. initial public offering. Luxembourg-based Skype tentatively put the value of the offering at $100 million, but that’s a rough estimate only used as a basis for the filing fee for the Securities and Exchange Commission. Skype did not say when its shares would go on sale, or at what price. It expects to list on the Nasdaq Stock Market under an unspecified symbol.