KCheckGMail 0.5.8 release was delayed for more than an year (I think). The day I finally release
KCheckGMail Google changed GMail's login procedure. 0.5.8 useful lifetime was less than a day.
I already updated both KDE3 and KDE4 versions to work with the new GMail login procedure. You can download the latest snapshots from the
development repo.
For the KDE3 version grab the latest snapshot from the
0_5_8_x branch.
For the KDE4 version grab the latest snapshot from the
kde4-port branch.
p.s. Hosted domain accounts not yet updated. I don't have an account to test it.