I play exactly what is in Version 2 of the Irreplaceable chords
(http://www.ultimate-guitar.com/tabs/b/beyonce_knowles/irreplaceable_ver2_crd.htm.)
but I think this might make a better bridge:  

Capo 3



Em (022000@1)                   DSo (xx0232@1)since I'm not your everything

               Cadd9How (x32030@1)about I be nothing

G (320003@1)               Emnothing (022000@1)at all to you?

                    ABaby (x02220@1)I won't shed a tear for you

CI (x32010@1)won't lose a wink of sleep 

D (xx0232@1)                  
cuz the truth of the matter is

Cadd9 (x32030@1)          EmG
replacing you is so easy...



The rest of the song is just repetitions of G, D, A, C as shown in Version 2.