It's a good show you ought to try it. just because two female coworkers are don't mean they have to be lesbians.
If someone really wants that angle, the gag reel from season 1 shows the two lead actors joking around in that vein.
Incidentally, those who like Rizzoli & Isles may want to keep an eye on Scott & Bailey, a British series starring Suranne Jones (who played Idris in Doctor Who last spring), who co-created it. From what I've seen it's similar to R&I, but with more of a Cagney & Lacey feel to it. And no, the two leads don't appear to be gay in this one either; sorry.
do they play it on bbcamerica?