Mak,
Fractional T1 is one or more channels bundled together and sold to to you as a set. This lets you buy less than a full T1's bandwidth at (mostly pro-rated) fractional cost.
Channelized T1, on the other hand, has 24 individual channels, each capable of carrying voice or data. The full set of channels has the same speed as a full T1, but the individual channels can be split into voice and data lines using a CSU/DSU. Again, "fractions" of the T1 line can be used for Internet connectivity, voice or not at all.
Cisco has nifty one and two port cards, "multiflex cards" that combine WAN Interface Card (WIC) and Voice Interface Card (VIC) functionality for 2600, 2800, 3600, 3700, and 3800 multiservice routers (http://www.cisco.com/en/US/products/hw/routers/ps259/products_data_sheet09186a0080091b9c.html)
Cheers,
Josef.
PS - rate if it helps ;-)
