discovering what is left when a particular segment is removed from a word (e.g., Say “smile” without the “sss.” Say “team” without the “mmm”);
breaking one-syllable words into their phonemes; and
blending phonemes to make a word (What word does “mmm…ooo…nnn” make?).
Commercial products (books, software) for preschool teachers, with games involving these kinds of activities, are becoming more and more available. Talking about phonemes can also be integrated with letter learning, so that children can be introduced to the sounds of letters (i.e., the phonemes that they stand for) as well as to their names.
Activities
Children should play with sound and rhymes through a variety of games and songs. Examples of these games and songs follow
Sing songs that play with sound 
I Can Hear the Rain
Pitter patter, pitter patter, I can hear the rain.
Pitter patter, pitter patter, I can hear the rain.
OO, OO, I can hear the wind.
OO, OO, I can hear the wind.