I have read the VoxEU.org book for G20 leaders. It has important ideas as well as warnings for the upcoming meeting.
Many authors agree that the IMF should be reformed and its lending capacity should be boosted (Rodrik, Buiter, Rajan, Eichengreen, Ito, Dobson, Berglöf & Zettelmeyer). Some propose new global institutions like World Financial Organization in the image of WTO (Eichengreen; note: this is, however, is not a substitute for IMF), or International Bank Charter for the world's largest banks (Claessens). Park suggests to apply the East Asia's model of reserve pooling (SRPA, self-managed reserve pooling arrangement) to broader areas.
While coordination across countries is important, some authors warn against wasting time on trying to establish a grandiose global super-regulator (most notably Dobson and Gürkaynak, but also Buiter). But Buiter proposes a uniform global regulatory framework for rating agencies. Many of them are also worried about the rising protectionism (Rodrik, Zedillo -- the latter uses the opportunity to remind the importance of Doha). However, Calvo thinks capital control might be allowed, at least as the second best proposition (Rodrik is surprised).
They seem to agree with the need for well-targeted fiscal expansion (most notably Alesina & Tabellini, Spence, Buiter, Rodrik), but do not approve too much government intervention (most notably Dobson). Explicitly, Alesina & Tabellini do not want bailout for unproductive industries like autoindustry (i.e. GM in USA) or failing airlines in Italy.
Other proposals that directly reflect on the current financial meltdown include cutting interest rates (Alesina & Tabellini)*, removing mortgages from damaged balance sheets, resetting terms, limiting foreclosures, and evaluating collateralized and structured assets (Spence, to some extent Buiter), returning to narrow banking, i.e. choosing between commercial banking or investment banking (De Grauwe), improving surveillance mechanism and reinforcing liquidity support to small nations (Ito).
*) It is worth considering also that economists who are not in the book like Jim Hamilton and Krugman are skeptical about lowering interest rates.