In Blog Config > Preferences, choose ascending for Order of entries displayed. Is that what you're looking for?

From the manual:
sort_order="ascend|descend''
Specifies the sort order for this particular MTEntries tag; this can be used to override the globally set Sort Order for Entries, set in your blog configuration. Valid values are ascend and descend.

So you'd override it in your Main Index by adding sort_order="descend'' to MTEntries.

is there any way to have archives display in reverse chronological format ? that is the beginning of the month at the top of the page instead of at the bottom ?

TIA
-imuse-
still getting to grips with this blog thang. rendered slightly helpless by the theft of his notebook

erm ... almost. i was hoping to keep the 'descending' format on my main page, and use 'ascending' posts just on the monthly archive pages.

-imuse-