Hi Bro... Let me explain little bit according to product wise... means like MS SQL Server, IBM DB2, Oracle, MySQL etc lots of RDBMS product... most popular is MS SQL SERVER the reason is cost and resource available... but other product also doing very good ..

What mean Oracle developer, SQL server dev, mysql Dev ... that means you must have these product knowledge also plus know of skript language to develop object for these... that common language is SQL skript language.

Job search time best is between Feb to Oct.. what I observe , my personal view .. might be differ from others.

Now availability, if you can show more then 4+ years of exp.. you will get 2-3 calls daily for sql server dba jobs, so the market is very demanding but supply is low, you can see by this call per day.

Bill rate for C2C start from 40/hr for 4 years exp... if you have 6+ exp then it goes between 55-60$/hr very easily... fulltime W2 start with 70K to 120K easily ... that all matter of bargaining.

Hope you got the point....