I contacted T-Mobile today to see if there was any news on the release. The lady basically said there is a new Nokia and a new Samsung phone coming out at the end of this month and that is all she knew about. She said "big releases" like the 8300 are not announced well in advance and they (meaning customer service and retail outlets) won't know about it until about a week before the release. She basically said to keep my eyes out on their website and see what happens. IOW, don't hold my breath.
On a side note. I just got an email from work, the CEO. It seems we're switching everyone from T-Mobile to AT&T! So, looks like I'll be getting a Curve sooner than I expected...