I am wondering if my T-mobile G1 (bought in usa) will work with Koodo mobile (which uses telus's service)

Telus (koodo) uses 3G HSPA and CDMA.

and as of what I know, the g1 is the folowing:
2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 2100
HSDPA 1700 / 2100 - American version