The v$backup view that Gregg mentioned will work fine if the backup is currently running. I'm not sure what you are asking here. If you want some kind of history of the backups taken using alter tablespace begin/end backup commands, then no, I don't believe there is a data dictionary table that archives that information. For that, you'd need something like the RMAN recovery catalog, which will keep a historical listing of all backups taken whether they be control file, archive log, datafile, or tablespace backups.
FILE# File identifier
STATUS File status: NOT ACTIVE, ACTIVE (backup in progress), OFFLINE NORMAL, or description of an error
CHANGE# System change number when backup started
TIME Time the backup started
Others information can be found in other v$backup views:
RECID Backup datafile record ID
STAMP Backup datafile record stamp
SET_STAMP Backup set stamp
SET_COUNT Backup set count
FILE# Datafile number. Set to 0 for control file
CREATION_CHANGE# Creation change of the datafile
CREATION_TIME Creation timestamp of the datafile
RESETLOGS_CHANGE# Resetlogs change# of the datafile when it was backed up
RESETLOGS_TIME Resetlogs timestamp of the datafile when it was backed up
INCREMENTAL_LEVEL (0-4) incremental backup level
INCREMENTAL_CHANGE# All blocks changed after incremental change# is included in this backup. Set to 0 for a full backup
CHECKPOINT_CHANGE# All changes up to checkpoint change# are included in this backup
CHECKPOINT_TIME Timestamp of the checkpoint
ABSOLUTE_FUZZY_CHANGE# Highest change# in this backup
MARKED_CORRUPT Number of blocks marked corrupt
MEDIA_CORRUPT Number of blocks media corrupt
LOGICALLY_CORRUPT Number of blocks logically corrupt
DATAFILE_BLOCKS Size of the datafile in blocks at backup time. This value is also the number of blocks taken by the datafile restarted from this backup
BLOCKS Size of the backup datafile in blocks. Unused blocks are not copied to the backup
BLOCK_SIZE Block size
OLDEST_OFFLINE_RANGE The RECID of the oldest offline range record in this backup control file. 0 for datafile backups
COMPLETION_TIME The time completed
Others include v$backup_set, v$backup_redolog etc ...
Gregg is correct in that the v$backup_XXXX views are populated with some historical information, but I believe they are only populated by RMAN. So I guess you don't really need the catalog. However (and this again comes back to needing clarification from your original question) you can issue an ALTER TABLESPACE BEGIN BACKUP command and then phycially copy your datafiles for that tablespace without using RMAN at all, which I believe will NOT populate any of the v$backup_XXXX tables.
My apologies for getting back late at this but you guys did answer few of my concerns. To further clarify I wanted to know if historical backup information is kept somewhere in data dictionary table with/without the use of RMAN. I have used v$backup but again it does not contain all the information I want. I am thinking of creating a table of my own and code my backup script such that after a tablespace backup is successfull, I make an entry with information such as tablespace name, time etc.