As Charles Duffey has stated, XML parsers are best parsed with a proper XML parsing tools. For one time job the following should work.
grep -oPm1 "(?<=<title>)[^<]+"
Test:
$ echo "$data"
<item>
<title>15:54:57 - George:</title>
<description>Diane DeConn? You saw Diane DeConn!</description>
</item>
<item>
<title>15:55:17 - Jerry:</title>
<description>Something huh?</description>
$ title=$(grep -oPm1 "(?<=<title>)[^<]+" <<< "$data")
$ echo "$title"
15:54:57 - George: