1. A method of operating a wireless handheld device, comprising: upon receipt of a request to use a messaging service, displaying (i) a recipient field for entering a recipient, and (ii) a message composition field for entering a message to be sent to said recipient; thereafter, upon each keystroke entry of text into said recipient field: looking up address book entries from a local address book which match said text; and displaying a selection menu comprising (a) any address book entries from said local address book which match said text, (b) a look up option to look up matching entries from a global address book hosted at a remote server, and (c) cached global address book entries previously looked up from said global address book; upon selection of a given address book entry from said selection menu, populating said recipient field with said given address book entry, wherein said selection menu is a first selection menu, and said method further comprises: upon selection of said look up option: querying said remote server hosting said global address book with a string representing said text; and receiving matching entries in reply; displaying a second selection menu comprising said entries from said global address book which match said text, wherein said first selection menu further comprises (d) said text with a summary indication of contents of said second selection menu and wherein said summary indication comprises a count of said entries from said global address book which match said text.
1. A method of operating a wireless handheld device, comprising: upon receipt of a request to use a messaging service, displaying (i) a recipient field for entering a recipient, and (ii) a message composition field for entering a message to be sent to said recipient; thereafter, upon each keystroke entry of text into said recipient field: looking up address book entries from a local address book which match said text; and displaying a selection menu comprising (a) any address book entries from said local address book which match said text, (b) a look up option to look up matching entries from a global address book hosted at a remote server, and (c) cached global address book entries previously looked up from said global address book; upon selection of a given address book entry from said selection menu, populating said recipient field with said given address book entry, wherein said selection menu is a first selection menu, and said method further comprises: upon selection of said look up option: querying said remote server hosting said global address book with a string representing said text; and receiving matching entries in reply; displaying a second selection menu comprising said entries from said global address book which match said text, wherein said first selection menu further comprises (d) said text with a summary indication of contents of said second selection menu and wherein said summary indication comprises a count of said entries from said global address book which match said text. 2. The method of claim 1 , further comprising: upon selection of a given global address book entry from said second selection menu, caching said given global address book entry.