CallWave and XO Communications, Inc. Partner to Deliver CallWave's Mobile Applications to XO Communications Customers

SANTA BARBARA, Calif. -- June 1, 2005 -- CallWave, Inc. (NASDAQ: CALL), a leading provider of VoIP enhanced services, and XO Communications, Inc. (OTCBB: XOCM.OB), a leading national provider of telecommunications, Internet and web hosting services today announced that XO Communications will market CallWave's unique mobile applications to its hosting customers. CallWave's applications add powerful new features to any user's existing mobile services without the need for new hardware or telecommunications infrastructure. The marketing opportunity with XO Communications is a key part of CallWave's strategy to distribute its mobile applications through co-branded partnerships in order to reach new markets.

Under the agreement, XO Communications will advertise and market CallWave's mobile applications -- Mobile Call Screening(SM) and Mobile Call Transfer(SM) -- to their hosting customers through a variety of channels. CallWave's Mobile Call Screening allows users to listen to voice messages in real time on their current cell phone and, if they choose, interrupt the message to take the call. Mobile Call Transfer lets users instantly transfer a live cell phone call to a home or office phone. These features allow users to stretch their wireless minutes and improve call quality in areas of poor reception.

"CallWave's mobile phone applications provide a useful service at a great value," said Barbara Branaman, Vice President and General Manager of XO Communications' hosting business. "We expect our customers will appreciate having the ability to screen and transfer incoming mobile phone calls so that they can better manage their time and telecommunications budgets."

"We're excited to serve XO Communications' growing small business customer base," said David Hofstatter, President and CEO of CallWave. "Our enhanced mobile applications are uniquely positioned to help telecommunications companies like XO Communications improve their customers' existing phone services."

About XO Communications

XO Communications is a leading provider of national and local telecommunications services to businesses, large enterprises and telecommunications companies. XO offers a complete portfolio of services, including local and long distance voice, dedicated Internet access, private networking, data transport, and Web hosting services as well as bundled voice and Internet solutions. XO provides these services over an advanced, national facilities-based IP network and serves more than 70 metropolitan markets across the United States. For more information, visit www.xo.com.

About CallWave

CallWave (NASDAQ: CALL) is a leader in VoIP enhanced services for the consumer and small business markets. The company provides VoIP application services on a subscription basis that add features and functionality to both the landline and wireless telecommunications services used in mainstream homes and small offices. CallWave's proprietary VoIP software allows subscribers to get more out of their existing networks -- landline, mobile, and IP -- by adding software-based call-handling features, and by bridging all three networks to help subscribers get their important calls. Founded in 1998, CallWave is headquartered in Santa Barbara, California. For further information, please visit www.callwave.com.